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UNIVERSITY    OF    ILLINOIS    LIBRARY    AT    URBANA-CHAMPAIGN 


O-1096 


UNIVERSITY  OF  ILLINOIS 


e«f'/ 


Agricultural  Experiment  Station 


*^tu«?« 


SOIL  REPORT  No.  39 


LOGAN  COUNTY  SOILS 

Bt  R.  S.  smith.  B.  B.  DbTURK,  F.  0.  BAUER,  and  L.  H.  SMITH 


URBANA,  ILLINOIS,  OCTOBER,  1927 


The  Soil  Survey  of  Illinois  was  organized  under  the  general  supervision 
of  Professor  Cyril  G.  Hopkins,  with  Professor  Jeremiah  G.  Mosier  directly 
in  charge  of  soil  classification  and  mapping.  After  working  in  association 
on  this  undertaking  for  eighteen  years.  Professor  Hopkins  died  and  Profes- 
sor Mosier  followed  two  years  later.  The  work  of  these  two  men  enters  so 
intimately  into  the  whole  project  of  the  Illinois  Soil  Survey  that  it  is  im- 
possible to  disassociate  their  names  from  the  individual  county  reports. 
Therefore  recognition  is  hereby  accorded  Professors  Hopkins  and  Mosier  for 
their  contribution  to  the  work  resulting  in  this  publication. 


STATE  ADVISOBT  COMMITTEE  ON  SOIL  INVESTIGATIONS 

1926-1927 


Belph  Allen,  Delavan 

F.  I.  Mann,  Gilman 

N.  P.  Goodwin,  Palestine 


A.  N.  Abbott,  Morrison 
Q.  F.  Tullock,  Eockford 
W.  E.  Eiegel,  Tolono 


EESEAECH  AND  TEACHING  STAFF  IN  SOILS 
1926-1927 

Herbert  W.  Miunf  ord,  Director  of  the  Experiment  Station 
W.  L.  Burlison,  Head  of  Agronomy  Department 


Boil  Physics  otuJ  Mapping 
B.  S.  Smith,  Chief 
O.  I.  Ellis,  Assistant  Chief 

D.  C.  Wimer,  Assistant  Chief 

E.  A.  Norton,  Associate 
M.  B.  Harland,  Associate 
E.  S.  Stauffer,  Associate 

D.  C.  Maxwell,  Assistant 
M.  E.  Isaacson,  Assistant 

Soil  Fertility  and  Analysis 

E.  E.  DeTurk,  Chief 

V.  E.  Spencer,  Associate 

r.  H.  Crane,  Associate 

J.  C.  Anderson,  First  Assistant 

E.  H.  Bray,  First  Assistant 

E.  G.  Sieveking,  First  Assistant 

H.  A.  Lunt,  First  Assistant 

E.  Cowart,  Assistant 

M.  P.  Catherwood,  Assistant 

P.  M.  Willhite,  Assistant 


Soil  Experiment  Fields 
F.  C.  Bauer,  Chief* 
H.  J.  Snider,  Assistant  Chief 
John  Lamb,  Jr.,  Associate 
M.  A.  Hein,  Associate 
C.  J.  Badger,  Associate 
A.  L.  Lang,  Associate 
A.  TJ.  Thor,  First  Assistant 
J.  E.  McKittrick,  Assistant 
L.  B.  Miller,  Assistant 

Soil  Biology 

O.  H.  Sears,  Assistant  Chief 
F.  M.  Clark,  Assistant 
W.  E.  Carroll,  Assistant 
W.  E.  Paden,  Assistant 

Soils  Extension 

P.  C.  Bauer,  Professor* 
C.  M.  Linsley,  Associate 

Soil  Survey  Publications 
L.  H.  Smith,  Chief 
P.  W.  Gault,  Scientific  Assistant 
Nellie  Boucher  Smith,  Editorial 
Assistant 


Engaced  in  Soils  Extenaion  ss  well  as  in  Soil  Experiment  Fields. 


INTRODUCTORY  NOTE 

It  is  a  matter  of  common  observation  that  soils  vary  tremendously  in  their 
productive  power,  depending  upon  their  physical  condition,  their  chemical  com- 
position, and  their  biological  activities.  For  any  comprehensive  plan  of  soil 
improvement  looking  toward  the  permanent  maintenance  of  our  agricultural 
lands,  a  definite  knowledge  of  the  various  existing  kinds  or  types  of  soil  is  a 
first  essential.  It  is  the  purpose  of  a  soil  survey  to  classify  the  various  kinds  of 
soil  of  a  given  area  in  such  a  manner  as  to  permit  definite  characterization  for 
description  and  for  mapping.  With  the  information  that  such  a  survey  affords, 
every  farmer  or  landowner  of  the  surveyed  area  has  at  hand  the  basis  for  a 
rational  system  of  improvement  of  his  land.  At  the  same  time  the  Experiment 
Station  is  furnished  an  inventory  of  the  soils  of  the  state,  upon  which  intelli- 
gently to  base  plans  for  those  fundamental  investigations  so  necessary  for  solving 
the  problems  of  practical  soil  improvement. 

This  county  soil  report  is  one  of  a  series  reporting  the  results  of  the  soil 
survey  which,  when  completed,  will  cover  the  state  of  Illinois.  Each  county 
report  is  intended  to  be  as  nearly  complete  in  itself  as  it  is  practicable  to  make 
it,  even  at  the  expense  of  some  repetition.  There  is  presented  in  the  form  of  an 
Appendix  a  general  discussion  of  the  important  principles  of  soil  fertility,  in 
order  to  help  the  farmer  and  landowner  to  understand  the  significance  of  the 
data  furnished  by  the  soil  survey  and  to  make  intelligent  application  of  the  same 
in  the  maintenance  and  improvement  of  the  land.  In  many  cases  it  will  be  of 
advantage  to  study  the  Appendix  in  advance  of  the  soil  report  proper. 

Data  from  experiment  fields  representing  the  more  extensive  types  of  soil, 
and  furnishing  valuable  information  regarding  effective  practices  in  soil  man- 
agement, are  embodied  in  the  form  of  a  Supplement.  This  Supplement  should 
be  referred  to  in  connection  with  the  descriptions  of  the  respective  soil  types 
found  in  the  body  of  the  report. 

While  the  authors  must  assume  the  responsibility  for  the  presentation  of 
this  report,  it  should  be  understood  that  the  material  for  the  report  represents 
the  contribution  of  a  considerable  number  of  the  present  and  former  members 
of  the  Agronomy  Department  working  in  their  respective  lines  of  soil  mapping, 
soil  analysis,  and  experiment  field  investigation.  In  this  connection  special 
recognition  is  due  the  late  Professor  J.  G.  ]Mosier,  under  whose  direction  the  soil 
survey  of  Logan  county  was  conducted,  and  to  Mr.  F.  A.  Fisher  and  Mr.  0.  I. 
Ellis  who,  as  leaders  of  the  field  parties,  were  in  direct  charge  of  the  mapping. 


CONTENTS  OF  SOIL  REPORT  NO.  39 
LOGAN  COUNTY  SOILS 

PAGE 

LOCATION  AND  CLIMATE  OF  LOGAN  COUNTY 1 

AGRICULTURAL   PRODUCTION    1 

SOIL  FORMATION   2 

Glaciation 2 

Physiography    and    Drainage 3 

Soil  Development 4 

Soil  Groups 4 

INVOICE  OF  THE  ELEMENTS  OF  PLANT  FOOD  IN  LOGAN  COUNTY  SOILS 6 

The  Upper    Sampling   Stratum 7 

The  Middle  and  Lower  Sampling  Strata 9 

DESCRIPTION  OF  SOIL  TYPES 14 

Upland  Prairie  Soils 14 

Upland  Timber  Soils 17 

Terrace  Soils   19 

Swamp  and  Bottom-Land  Soils 20 

APPENDIX 
EXPLANATIONS  FOR  INTERPRETING  THE  SOIL  SURVEY 22 

Classification   of   Soils 22 

Soil  Survey  Methods 24 

PRINCIPLES  OF  SOIL  FERTILITY 25 

Crop  Requirements  with  Respect  to  Plant-Food  Materials 26 

Plant-Food  Supply  26 

Liberation  of  Plant  Food 28 

Permanent   Soil   Improvement 29 

SUPPLEMENT 

EXPERIMENT  FIELD  DATA 39 

The  Mt.  Morris  Field 40 

The  Kewanee  Field   42 

The  Bloomington  Field 44 

The  Aledo  Field   45 

The  Hartsburg  Field   50 


LOGAN  COUNTY  SOILS 

By  R.   S.  smith,  E.  E.   DeTURK,  F.  C.   BAUER,  and  L.   H.   SMITHS 

LOCATION  AND  CLIMATE  OF  LOGAN  COUNTY 

Logan  county  is  in  almost  the  exact  center  of  the  state  of  Illinois.  It  has 
a  total  area  of  616.43  square  miles,  three-quarters  of  which  is  upland. 

The  climate  of  Logan  county  is  typical  of  central  Illinois.  It  is  characterized 
by  a  wide  range  between  the  extremes  of  winter  and  summer  and  has  an 
abundant,  usually  well-distributed  rainfall.  The  great  range  in  temperature 
for  any  one  year  for  the  sixteen-year  period  from  1910  to  1925,  as  recorded  at 
the  Lincoln  Weather  Bureau  Station,  was  130  degrees,  in  1914.  The  highest 
temperature  recorded  was  105",  in  1918;  the  lowest,  29°  below  zero,  in  1914. 
The  average  date  of  the  last  killing  frost  in  spring  is  May  4 ;  the  earliest  in  the 
fall,  October  13.     The  average  length  of  the  growing  season  is  162  days. 

The  average  annual  rainfall,  as  recorded  for  this  sixteen-year  period  at 
Lincoln,  was  35.54  inches.  The  average  rainfall  by  months  for  this  period  was 
as  follows:  January,  1.91  inches;  February,  1.48;  March,  3.12;  April,  3.45; 
May,  4.30;  June,  3.47;  July,  2.95;  August,  3.40;  September,  3.82;  October, 
2.90;   November,  2.07;   December,  1.99. 

AGRICULTURAL  PRODUCTION 

Logan  county  is  agricultural  in  its  interests,  over  90  percent  of  the  land 
being  suitable  for  farming.  According  to  the  Fourteenth  Census  of  the  United 
States  there  were  2,234  farms  in  the  county  in  1920,  a  decrease  of  86  since  1910 
and  171  since  1900.  About  65  percent  were  operated  by  tenants,  an  increase  of 
about  6  percent  in  twenty  years. 

The  principal  crops  are  those  common  to  the  corn  belt,  as  shown  by  the 
following  figures  for  the  year  1919. 

Crops  Acreage  Production  Yield  per  acre 

Corn 126,220  5,193,270  bu.  41.1  bu. 

Oats 56,193  1,692,878  bu.  30.1  bu. 

Wheat 89,448  1,852,127  bu.  20.7  bu. 

Timothy 4,820  6,179  tons  1.28  tons 

Timothy  and  clover  mixed....  2,957  '  3,857  tons  1.30  tons 

Clover 13,232  14,494  tons  1.09  tons 

Alfalfa 783  2,029  tons  2.59  tons 

Silage  crops 659  6,002  tons  9.10  tons 

Corn  for  forage 869  2,393  tons  2.75  tons 

These  figiares  are  for  but  a  single  year.  For  the  ten-year  period  1916  to  1925  the 
U.  S.  Department  of  Agriculture  gives  the  average  yield  of  corn  as  40.5  bushels ; 
oats,  35.0  bushels;  winter  wheat,  21.4  bushels;   tame  hay,  1.29  tons. 

The  total  value  of  all  livestock  and  livestock  products  produced  in  1919  was 
$5,858,500,  or  a  little  over  one-third  the  value  of  crops  produced  that  year.    The 


'  R.  S.  Smith,  in  charge  of  soil  survey  mapping;    E.  E.  DeTurk,  in  charge  of  soil  analysis; 
F.  C.  Bauer,  in  charge  of  experiment  fields;    L.  H.  Smith,  in  charge  of  publications. 


2  Soil  Report  No.  39 

following  figures,  taken  from  the  1920  Census,  show  the  character  of  the  live- 
stock interests  in  the  county. 

Animals  and  Animal  Products                               Number  Value 

Ho^  SOS 17,999  $1,781,591 

Mules 2,342  323,669 

.    Beef  cattle 8,778  548,118 

Dairy  cattle 13,287  894,089 

Sheep 4,760  55,518 

Swino 47,721  896,473 

Chickens   and   other   poultry 280,562  272,718 

Chickens  and  eggs  produced 679,102 

Dairy  products "  produced 373,954 

SOIL  FORMATION 

GLACIATION 

One  of  the  most  important  periods  in  the  geological  history  of  the  county, 
from  the  standpoint  of  soil  formation,  was  the  Glacial  period.  During  and  imme- 
diately following  this  remote  period,  the  material  that  later  formed  the  mineral 
portion  of  the  soils  was  being  deposited.  At  that  time  snow  and  ice  accumulated 
in  the  region  of  Labrador  and  to  the  west  of  Hudson  Bay  to  such  an  amount  that 
the  mass  pushed  outward  from  these  centers,  chiefly  southward,  until  a  region 
was  reached  where  the  ice  melted  as  rapidly  as  it  advanced.  In  moving  across 
the  country  from  the  far  north,  the  ice  gathered  up  all  sorts  and  sizes  of  material, 
including  clay,  silt,  sand,  gravel,  boulders,  and  even  immense  masses  of  rock. 
Some  of  these  materials  were  carried  for  hundreds  of  miles  and  rubbed  against 
surface  rocks  and  against  each  other  until  largely  ground  into  powder.  When 
the  ice  sheet,  or  glacier,  reached  the  limit  of  its  advance,  the  rock  material  carried 
by  it  accumulated  along  the  front  edge  in  a  broad,  undulating  ridge  or  moraine. 
With  rapid  melting,  the  terminus  of  the  glacier  receded,  and  the  material  was 
deposited  somewhat  irregularly  over  the  area  previously  covered.  The  mixture 
of  materials  deposited  by  the  glacier  is  known  as  boulder  clay,  till,  glacial  drift, 
or  simply  drift.  The  average  depth  of  this  deposit  over  the  state  of  Illinois  is 
estimated  at  115  feet. 

Previous  to  the  ice  invasion  this' region  generally  was  not  well  suited  to 
agriculture  because  of  its  rough  and  hilly  character.  Logan  county  was  covered 
by  the  Illinoisan  glaciation  and  in  the  northeast  corner  by  the  Wisconsin  glacia- 
tion.  The  general  effect  of  these  glaciers  was  to  change  the  surface  from  hilly 
to  gently  undulating  by  rubbing  down  the  hills  and  filling  the  valleys.  Several 
moraines  were  formed  in  this  county. 

Altho  it  did  not  touch  the  county,  a  later  ice  sheet,  known  as  the  lowan, 
played  an  important  role  in  the  formation  of  the  soils.  During  the  time  Avhen 
the  melting  ice  front  of  this  lowan  glacier  lay  to  the  north  of  the  area  now 
comprizing  Logan  county,  immense  volumes  of  water,  heavily  laden  with  fine 
sediment,  flowed  from  the  ice.  This  water  filled  the  drainage  channels  and 
overflowed  the  adjacent  lowlands,  forming  terraces.  Following  each  flood  state, 
the  water  would  recede  and  the  sediment  which  had  been  deposited  would  be 
picked  up  by  the  wind  and  redeposited  on  the  upland. 


Logan  County  3 

This  wind-blown  dej)osit,  known  as  loess,  varies  from  60  to  75  inches  in 
thickness  over  much  of  the  county  and  apparently  it  is  the  material  from  which 
the  upland  soils  of  Logan  county  are  formed. 

PHYSIOGRAPHY  AND  DRAINAGE 

The  topography  of  Logan  county  is  favorable  to  good  surface  drainage  with 
the  exception  of  a  few  areas,  notably  in  the  vicinity  of  Elkhart,  in  the  region 
south  of  Mt.  Pulaski,  and  between  Hartsburg  and  Emden.  Even  these  rela- 
tively flat-lying  areas,  however,  are  sufficiently  undulating  so  that  drainage  may 
be  provided  without  difficulty.     The  north  corner  of  the  county  in  the  region 


R4W 


R3W 


T?2W 


^  WISCONSIN  MORAINES 


TERRACE 


ILLINOISAN  MORAINES 


BOTTOM    LAND 


Fig.  1. — Drainage  Map  of  Logan  County  Showing  Stream  Courses,  Glaciations, 
AND  Terrace  and  Bottom-Land  Areas 


4  Soil  Report  No.  39 

of  San  Jose  is  rolling  and  has  a  dune-like  topography.     The  soil  map  shows  a 
number  of  morainal  hills  south  and  west  of  Mt.  Pulaski. 

The  drainage  of  the  county  is  well  taken  care  of  by  Salt  creek  and  its 
tributaries.  All  the  drainage  of  the  county  finds  its  way  into  Sangamon  river 
thru  Salt  creek,  with  the  exception  of  a  few  square  miles  in  the  southwest  corner, 
which  drain  directly  into  the  Sangamon.  The  wide  bottoms  and  terraces  along 
Salt  creek  and  its  tributaries,  Deer  creek,  Kickapoo  creek,  and  Sugar  creek,  show 
that  stream  action  was  much  more  vigorous  at  one  time  in  the  history  of  this 
region  than  it  is  now. 

SOIL  DEVELOPMENT 

During  the  time  which  has  elapsed  since  the  last  ice  invasion,  weathering 
and  other  processes  have  been  active,  resulting  in  the  formation  of  the  soils  of 
the  county  as  we  know  them  today.  When  first  deposited,  the  general  composi- 
tion of  any  soil  material,  particularly  loess,  is  rather  uniform.  With  the  passing 
of  time,  however,  various  physical,  chemical,  and  biological  agencies  of  weather- 
ing form  soil  out  of  the  parent  material  by  some  or  all  of  the  following  processes : 
the  leaching  of  certain  elements,  the  accumulation  of  others ;  the  chemical  reduc- 
tion of  certain  compounds,  the  oxidation  of  others;  the  translocation  of  the 
finer  soil  particles,  and  the  arrangement  of  them  into  zones  or  horizons;  and 
the  accumulation  of  organic  matter  from  the  growth  and  decay  of  vegetable 
material.  One  of  the  very  pronounced  characteristics  observed  in  most  soils  is 
that  they  are  composed  of  more  or  less  distinct  strata,  called  horizons.  As  ex- 
plained somewhat  more  fully  in  the  Appendix,  these  horizons  are  named,  from 
the  surface  down :  A,  the  layer  of  extraction ;  B,  the  layer  of  concentration  or 
accumulation;  and  C,  the  layer  of  less-altered  material,  or  the  layer  in  which 
weathering  has  had  less  effect.  The  development  of  horizons  in  a  soil  is  an 
indication  of  its  age. 

SOIL  GROUPS 

The  soils  of  Logan  county  have  been  divided  into  four  groups,  as  follows: 

Upland  Prairie  Soils,  dark  colored  and  usually  rich  in  organic  matter,  the 
organic  matter  having  been  derived  from  the  decaying  roots  of  the  wild  prairie 
grasses  which  occupied  this  land  for  thousands  of  years. 

Upland  Timber  Soils,  including  those  zones  along  stream  courses  over  which 
forests  grew  for  a  long  period  of  time.  These  contain  in  general  less  organic 
matter  than  the  prairie  soils. 

Terrace  Soils,  including  bench  lands  and  second  bottoms  formed  by  deposits 
from  flooded  streams  overloaded  with  sediment,  perhaps  at  the  time  of  the  melt- 
ing of  the  glaciers. 

Swamp  and  Bottom  Lands,  which  include  the  flood  plains  along  the  streams 
and  some  poorly  drained  muck  and  peat  areas.  The  soil  map  shows  the  Swamp 
and  Bottom  Lands  as  divided  into  two  groups,  the  Old  and  the  Late.  This 
division,  as  made,  was  geological,  but  according  to  the  present-day  conception 
of  the  matter  it  has  no  significance  in  a  soil  classification ;  hence  for  the  purpose 
of  describing  the  various  swamp  and  bottom-land  types,  the  two  groups  are  com- 
bined into  one. 


LEGEND 

200     Ulinoisan  Moraines 

/lOO     Middle  Ulinoisan  Glaciation 

900    Early  Wisconsin  Moraines 

UPLAND   PRAIRIE   SOILS 

26         Brown  Silt  Loam 


UPLAND  TIMBER   SOILS 


Yellow-Gray  Silt  Loam 


35        Yellow  Silt  Loam 


6«-       Yellow-Gray  Sandy  Loam 


1300   OLD  SWAMP  AND   BOTTOM-LAND   SOILS 
Deep  Brown  Silt  Loam 

320       Black  Clay  Loam 


Brown  Clay  Loam 


20        Black  Clay  Loam 


19        Brown  Clay  Loam 


I36«-      Mixed  Loam 


28        Brown-Gray  Silt  Loam  On  Tight  Clay 


60         Brown  Sandy  Loam 


SOIL  SURVEY  MA 

UNIVERSITY  OF  ILLINOIS  AGR 


} 


COUNTY 


920-^ 
920O- 


1400   LATE  SWAMP  AND  BOTTOM-LAND   SOILS 


l«6       Deep  Brown  Silt  Loam 


wad  :     Black  Clay  Loam 


Bfown  Clay  Loam 


Mixed  Loam 


1500  TERRACE   SOILS 
1527       Brown  Silt  Loam  Over  Sand  Or  Gravel 


RESIDUAL  SOILS 


1520       Black  Clay  Loam  Over  Sand  Or  Gravel 


ISS6       Brown  Sandy  Loam  Over  Sand  Or  Gravel 


IS36       Yellow-Gray  Silt  Loam  Over  Sand  Or  Gravel 


IS28       Brown-Gray  Silt  Loam  On  Tight  Clay 


^         Rock  Outcrop 

CONVENTIONAL   SIGNS 
I      I       Railroads 
,     ,    ,       Electric  Roads 
=^^3^     Public  Roads 
_^^^,,     Private  Roads 
j._i.j.-i-    Morainal  Boundaries 


Scale 

O    Mt   M:  1 2  Miles 


OF  LOGAN  COUNTY 
ULTURAL  EXPERIMENT  STATION 


Logan  County 
Table  1. — Soil  Types  of  Logan  County,  Illinois 


Soil 
tvpe 
No. 


Name  of  type 


Area  in 

square 

miles 


Area 

Percent 

m 

of  total 

acres 

area 

Upland  Prairie  Soils  (200,  400,  900) 

2261 

426 1- 

Brown  Silt  Loam 

369.66 

83.66 

.39 

1.15 

236  582 

53  542 
250 
736 

59.97 

9261 

420l 

Black  Clav  Loam 

13  57 

920/ 
428\ 
928/ 
2601 
460/ 

Brown-Gray  Silt  Loam  On  Tight  Clay 

Brown  Sandy  Loam 

.06 
19 

454.86 

291   110 

73.79 

Upland  Timber  Soils  (200,  400,  900) 

2341 

4341' 

Yellow-Gray  Silt  Loam 

35.91 

5.98 

.14 
.39 

22  982 

3  827 

90 
250 

5.83 

9341 

2351 
435^ 

Yellow  Silt  Loam 

.97 

935J 

464 

419 

Yellow-Gray  Handy  Loam 

Brown  Clay  Loam 

.02 
.06 

42.42 

27  149 

6.88 

Terrace  Soils  (1500) 


1527 

Brown  Silt  Loam  Over  Sand  or  Gravel 

38.35 

24  544 

6.22 

1520 

Black  Clay  Loam  Over  Sand  or  Gravel 

4.16 

2  662 

.68 

1566 

Brown  Sandy  Loam  Over  Sand  or  Gravel .  .  . 

.33 

211 

.05 

1536 

Yellow-Gray  Silt  Loam  Over  Sand  or  Gravel 

3.17 

2  029 

.50 

1528 

Brown-Gray  Silt  Loam  On  Tight  Clay 

5.72 

3  661 

.93 

51.73 

33  107 

8.38 

Swamp  and  Bottom-Land  Soils  (1300,  1400)' 


1326 
1426 
1320 
1420 
1319 
1419 
1354 
1454 


Deep  Brown  Silt  Loam. 

Black  Clay  Loam 

Brown  Clay  Loam 

Mixed  Loam 


39.96 

12.00 

8.26 

7.11 


67.33 


25  574 
7  680 
5  286 
4  550 


43  090 


6.49 
1.95 
1.34 
1.15 


10.93 


Miscellaneous 


Sand  or  Gravel  Pit . 

Water.  .■ 


Total. 


.07 
.02 


.09 


616.43 


45 
13 


58 


394  514 


.01 
.01 


.02 


100,00 


'These  1300  and  1400  groups  are  differentiated  on  the  map  but  not  in  the  descriptions,  as  ex- 
plained on  page  4. 

Table  1  gives  the  list  of  soil  types  in  Logan  county,  the  area  of  each  in 
square  miles  and  in  acres,   and  also  the  percentage  of  the  total  area.      The 


6  Soil  Report  No.  39 

accompanying  map,  shown  in  2  sections,  gives  the  location  and  boundary  of 
each  soil  type  which  has  been  mapped  in  the  county. 

For  explanations  concerning  the  classification  of  soils  and  the  interpretation 
of  the  map  and  tables,  the  reader  is  referred  to  the  first  part  of  the  Appendix. 

INVOICE  OF  THE  ELEMENTS  OF  PLANT  FOOD 
IN  LOGAN  COUNTY  SOILS 

In  order  to  obtain  a  knowledge  of  its  chemical  composition,  each  soil  type 
is  sampled  in  the  manner  described  below  and  subjected  to  chemical  analysis  for 
its  important  plant-food  elements.  For  this  purpose  samples  are  taken  usually 
in  sets  of  three  to  represent  different  strata  in  the  top  40  inches  of  soil ;  namely, 
an  upper  stratum  (0  to  6%  inches),  a  middle  stratum  (6%  to  20  inches),  and  a 
lower  stratum  (20  to  40  inches). 

These  sampling  strata  correspond  approximately  in  the  common  kinds  of 
soil  to  2  million  pounds  per  acre  of  dry  soil  in  the  upper  stratum,  and  to  two 
times  and  three  times  this  quantity  in  the  middle  and  lower  strata  respectively. 
This,  of  course,  is  a  purely  arbitrary  division  of  the  soil  section,  very  useful  in 
arriving  at  a  knowledge  of  the  quantity  and  distribution  of  the  elements  of 
plant  food  in  the  soil;  but  it  should  be  borne  in  mind  that  these  strata  seldom 
coincide  with  the  natural  strata  as  they  actually  exist  in  the  soil  and  which  are 
referred  to  in  describing  the  soil  types  as  "horizons  A,  B,  and  C."  By  this 
system  of  sampling  we  have  represented  separately  three  zones  for  plant  feeding. 
The  upper,  or  surface  layer,  includes  at  least  as  much  soil  as  is  ordinarily  turned 
with  the  plow,  being  the  part  with  which  the  farm  manure,  limestone,  phosphate, 
or  other  fertilizing  material  is  incorporated. 

The  chemical  analysis  of  a  soil,  obtained  by  the  methods  here  employed, 
gives  the  invoice  of  the  total  stock  of  the  several  plant-food  materials  actually 
present  in  the  soil  strata  sampled  and  analyzed.  It  should  be  understood,  how- 
ever, that  the  rate  of  liberation  from  their  insoluble  forms,  a  matter  of  at  least 
equal  importance,  is  governed  by  many  factors,  and  therefore  is  not  necessarily 
proportional  to  the  total  amounts  present. 

For  convenience  in  making  application  of  the  chemical  analyses,  the  results 
as  presented  here  have  been  translated  from  the  percentage  basis  and  are  given 
in  the  accompanying  tables  in  terms  of  pounds  per  acre.  In  this  the  assumption 
is  made  that  for  ordinary  types  a  stratum  of  dry  soil  of  the  area  of  an  acre  and 
6%  inches  thick  weighs  2  million  pounds.  It  is  understood,  of  course,  that  this 
value  is  only  an  approximation,  but  it  is  believed  that  with  this  understanding 
it  will  suffice  for  the  purpose  intended.  It  is  a  simple  matter  to  convert  these 
figures  back  to  the  percentage  basis  in  case  one  desires  to  consider  the  information 
in  that  form. 

With  respect  to  the  presence  of  limestone  and  acidity  in  different  strata,  no 
attempt  is  made  to  include  in  the  tabulated  results  figures  purporting  to  represent 
their  averages  for  the  respective  types,  because  of  the  extreme  variations  fre- 
quently found  within  a  given  soil  type.  In  examining  each  soil  type  in  the  field, 
however,  numerous  qualitative  tests  are  made  which  furnish  general  information 


LEGEND 


200     lllinoisan  Moraines 

AGO     Middle  lllinoisan  Qlaciation 

900     Early  Wisconsin  Moraines 

UPLAND   PRAIRIE   SOILS 

26         Brown  Silt  Loam 

20        Black  Clay  Loam 


UPLAND  TIMBER   SOILS 


Yellow-Gray  Silt  Loam 


1300   OLD   SWAMP  AND   BOTTOM-LAND   SOILS 


Deep  Brown  Silt  Loam 


35        Yellow  Silt  Loam 


1320       Black  Clay  Loam 


64-       Yellow-Gray  Sandy  Loam 


Brown  Clay  Loam 


28         Brown-Gray  Silt  Loam  On  Tight  Clay 


19        Brown  Clay  Loam 


\3SA-      Mixed  Loam 


60         Brown  Sandy  Loam 


SOIL  SURVEY  MA 
UNIVERSITY  OF  ILLINOIS  AGRp 


F 


SANaAMON 

1400  LATE  SWAMP  AND   BOTTOM-LAND  SOILS 
'^6   I    Deep  Brown  Silt  Loam 

•^0       Black  Clay  Loam 

Brown  Clay  Loam 


COUNTS' 

1500  TERRACE   SOILS 


Brown  Silt  Loam  Over  Sand  Or  Gravel 


MAC  ON  COUNTV 

RESIDUAL  SOILS 
"  Rock  Outcrop 


1520       Black  Clay  Loam  Over  Sand  Or  Gravel 


1566,       Brown  Sandy  Loam  Over  Sand  Or  Gravel 


CONVENTIONAL  SIGNS 
-H — I — 1~    Railroads 
-. — . — ^     Electric  Roads 
===     Public  Roads 


.  I4S*      Mixed  Loam 


IS36      Yellow-Gray  Silt  Loam  Over  Sand  Or  Gravel 


^.     Private  Roads 
J.    Morainal  Boundaries 


OF  LOGAN  COUNTY 
tJLTURAL  EXPERIMENT  STATION 


Brown-Gray  Silt  Loam  On  Tight  Clay 


Scale 

O     Ht    Va  1 2  Miles 


«  ■■  CO.LITH  BAtTlMOIte 


Logan  County  7 

regarding  the  soil  reaction,  and  in  the  discussion  of  the  individual  soil  types 
which  follows,  recommendations  based  upon  these  tests  are  given  concerning 
the  lime  requirement  of  the  respective  types.  Such  recommendations  cannot  be 
made  specific  in  all  cases  because  local  variations  exist,  and  because  the  lime 
requirement  may  change  from  time  to  time,  especially  under  cropping  and  soil 
treatment.  It  is  often  desirable,  therefore,  to  determine  the  lime  requirement  for 
a  given  field,  and  in  this  connection  the  reader  is  referred  to  the  section  in  the 
Appendix  dealing  with  the  application  of  limestone  (page  29). 

THE  UPPER  SAMPLING  STRATUM 

In  Table  2  are  reported  the  total  quantities  of  organic  carbon,  nitrogen, 
phosphorus,  sulfur,  potassium,  magnesium,  and  calcium  in  2  million  pounds  of 
surface  soil  of  each  type  in  Logan  county. 

In  connection  with  this  table  attention  is  called  to  the  variation  among  the 
soil  types  with  respect  to  their  content  of  the  different  plant-food  elements.  It 
will  be  seen  from  the  analyses  that  variations  in  the  organic-carbon  content  of 
the  different  soils  are  accompanied  by  similar  variations  in  the  nitrogen  content. 
The  organic-carbon  content,  which  serves  as  a  measure  of  the  total  organic  matter 
present,  averages  ten  times  that  of  the  total  nitrogen  in  the  upper  sampling 
stratum.  This  relationship  is  explained  by  the  well-established  facts  that  all 
soil  organic  matter  contains  nitrogen,  and  that  most  of  the  soil  nitrogen  (usually 
98  percent  or  more)  is  present  in  a  state  of  organic  combination.  This  close 
relationship  is  also  maintained  in  the  middle  and  lower  sampling  strata,  the 
ratio  usually  becoming  narrower  as  the  depth  increases. 

The  ranges  in  amount  of  organic  matter  and  nitrogen  are  very  wide.  The 
upland  prairie  soils  are  for  the  most  part  relatively  high  in  these  constituents, 
averaging  42,080  pounds  of  organic  carbon  in  an  acre,  while  the  upland  timber 
soils  are  fairly  low,  with  an  average  content  of  26,090  pounds  of  this  element. 
Black  Clay  Loam,  Upland,  contains  the  largest  amount  of  organic  carbon  of  any 
soil  in  the  county.  The  amount  found  in  this  type  is  69,970  pounds  an  acre,  with 
a  nitrogen  content  of  6,220  pounds.  The  lowest  amounrts  are  to  be  found  in  the 
more  or  less  sandy  types,  such  as  Brown  Sandy  Loam  and  Yellow-Gray  Sandy 
Loam  which,  because  of  their  loose,  open  character,  permit  the  rapid  oxidation 
of  the  organic  matter. 

Other  elements  are  not  so  closely  associated  with  each  other  as  are  organic 
matter  and  nitrogen.  However,  there  is  some  degree  of  correlation  between 
sulfur,  another  element  used  by  growing  plants,  and  organic  carbon.  This  is 
because  a  considerable  tho  varying  proportion  of  the  sulfur  in  the  soil  exists  in 
the  organic  form,  that  is,  as  a  constituent  of  the  organic  matter.  Most  of  the 
Logan  county  soils  are  fairly  well  supplied  with  sulfur,  only  the  two  sandy  types 
above  mentioned,  and  also  the  two  terrace  types,  Yellow-Gray  Silt  Loam  and 
Brown  Sandy  Loam,  exhibiting  very  low  values.  The  range  in  the  surface  soil 
is  from  a  minimum  of  340  pounds  an  acre  in  Yellow-Gray  Sandy  Loam  to  1,120 
pounds  in  Black  Clay  Loam,  Upland.  The  sulfur  content  of  the  soil  is  con- 
sistently 75  to  80  percent  as  high  as  the  phosphorus  in  the  upland  soils,  but  only 
50  percent  as  high  in  the  terrace  and  bottom-land  soils.     No  explanation  is 


8  Soil  Eepout  No.  39 

apparent  for  this  variation.  The  sulfur  available  to  crops  is  affected  not  only 
by  the  supply  in  the  soil  but  also  by  that  brought  down  from  the  atmosphere 
by  rain.  Sulfur  dioxid  escapes  into  the  air  in  the  gaseous  products  from  the 
burning  of  all  kinds  of  fuel,  particularly  coal.  The  gaseous  sulfur  dioxid  is 
soluble  in  water  and  consequently  it  is  dissolved  out  of  the  air  by  rain  and 
brought  to  the  earth.  In  regions  of  large  coal  consumption,  the  amount  of  sulfur 
thus  added  to  the  soil  is  large.  At  Urbana  during  the  eight-year  period  from 
1917  to  1924  there  was  added  to  the  soil  by  the  rainfall,  3.5  pounds  of  sulfur  an 
acre  a  month  as  an  average.  Similar  observations  have  been  made  in  other 
localities  for  shorter  periods.  At  Spring  Valley,  in  Bureau  county,  the  rainfall 
during  six  summer  months  in  1921  brought  down  34.5  pounds  of  sulfur  an  acre, 
or  an  average  monthly  precipitation  of  5.75  pounds.  The  maximum  for  a  single 
month  was  8.77  pounds,  in  June.  At  Toledo,  in  Cumberland  county,  from  April 
to  November,  1922,  the  average  precipitation  was  3  pounds  an  acre  a  month. 
The  precipitation  at  the  various  points  in  the  state  in  a  single  month  has  varied 
from  a  minimum  of  %  of  a  pound  to  over  10  pounds  an  acre.  These  figures  will 
afford  some  idea  of  the  amounts  of  sulfur  added  by  rain  and  also  of  the  wide 
variation  in  these  amounts  under  different  conditions. 

On  the  whole,  the  above  facts  would  indicate  that  the  sulfur  added  from 
the  atmosphere  supplements  that  contained  in  the  soil,  so  that  there  appears 
to  be  no  need  for  sulfur  fertilizers  in  Logan  county.  In  order  to  determine  defi- 
nitely the  response  of  crops  to  applications  of  sulfur  fertilizers,  experiments  with 
gypsum  have  been  started  at  five  experimental  fields,  one  of  which  is  in  Logan 
county.  These  fields  are  at  Raleigh,  Toledo,  Carthage,  Hartsburg,  and  Dixon. 
The  data  from  the  Hartsburg  experiment  field  are  given  in  the  Supplement  of 
this  Report,  page  50. 

With  regard  to  total  phosphorus,  the  two  upland  sandy  soils.  Brown  Sandy 
Loam  and  Yellow-Gray  Sandy  Loam,  are  very  deficient,  containing  only  600  and 
480  pounds  an  acre,  respectively,  in  the  surface  2  million  pounds.  Yellow  Silt 
Loam  is  but  little  better,  with  640  pounds  of  this  element.  Since  in  the  first  two 
of  these  three  types  the  phosphorus  percentage  is  no  higher  in  the  deeper  layers, 
not  much  could  be  expected  in  the  way  of  continued  high  production  on  these 
soil  types  without  phosphate  fertilization.  The  other  soils  of  the  county  range 
from  780  pounds  an  acre  in  Brown-Gray  Silt  Loam  On  Tight  Clay  to  1,860 
pounds  in  Black  Clay  Loam  Over  Sand  or  Gravel.  The  three  bottom-land  types 
are  all  rather  high,  containing  1,640  pounds  of  phosphorus  per  2  million  pounds 
of  surface  soil. 

The  potassium  content  of  the  soils  of  Logan  county  is  relatively  uniform. 
Except  for  the  two  sandy  types.  Brown  Sandy  Loam  and  Yellow-Gray  Sandy 
Loam,  the  range  is  from  approximately  30,000  to  38,000  pounds  an  acre,  with 
an  average  of  34,000  pounds.  The  two  sandy  types  above  mentioned  contain 
only  about  three-fourths  as  much  potassium  as  the  mean  of  the  rest  of  the 
county  and  have  the  additional  handicap  of  carrying  a  considerable  proportion 
of  their  potassium  content  in  the  coarse  sand  grains.  The  relatively  small  surface 
exposed  in  the  case  of  the  coarse  particles  greatly  lowers  the  solubility  and  availa- 
bility of  the  potassium  in  sand  soils.    This  is  partly  offset  by  the  greater  depth 


Logan  County  9 

of  the  feeding  zone  for  crop  roots  in  sandy  soils  as  compared  with  the  heavier 
types.  While  the  Experiment  Station  has  carried  out  no  field  experiments  in 
the  management  of  either  Brown  Sandy  Loam  or  Yellow-Gray  Sandy  Loam,  it 
would  appear  from  the  above  considerations  that  these  are  the  only  soil  types 
in  Logan  county  which  would  be  at  all  likely  to  respond  to  potassium  applications 
for  the  production  of  our  common  field  crops;  and  even  on  these  types  the  use 
of  well-planned  rotations,  the  return  of  crop  residues  and  manure,  and  the  plow- 
ing down  of  sweet  clover  will  go  a  long  way  toward  maintaining  an  adequate 
supply  of  this  element  in  the  available  condition  for  growing  crops. 

The  amounts  of  calcium  and  magnesium  in  soils  usually  vary  greatly  and 
this  is  the  case  in  the  soils  of  Logan  county.  The  range  in  calcium  content  in 
the  upper  6%  inches  is  from  4,740  pounds  to  18,890  pounds  in  2  million  pounds 
of  soil,  while  the  extremes  in  magnesium  content  are  even  farther  apart.  Mag- 
nesium has  never  been  found  deficient  for  crop  growth  in  the  soils  of  Illinois, 
nor  indeed  in  the  United  States.  Calcium,  however,  in  strongly  acid  soils  may 
become  available  too  slowly,  at  least  for  certain  crops  such  as  alfalfa  and  sweet 
clover.    This  is  a  defect  which  is  corrected  by  liming. 

THE  MIDDLE  AND  LOWER  SAMPLING  STRATA 

In  Tables  3  and  4  are  recorded  the  amounts  of  the  plant-food  elements  in 
the  middle  and  lower  sampling  strata.  In  comparing  these  strata  with  the  upper 
stratum,  or  with  each  other,  it  is  necessary  to  bear  in  mind  that  the  data  as  given 
for  the  middle  and  lower  sampling  strata  are  on  the  basis  of  4  million  and  6 
million  pounds  of  soil,  and  should  therefore  be  divided  by  2  and  3  respectively 
before  being  compared  with  each  other  or  with  the  data  for  the  upper  stratum, 
which  is  on  a  basis  of  2  million  pounds. 

Considering  the  data  in  this  way  it  will  be  noted  in  comparing  the  three 
strata  with  each  other  that  some  of  the  elements  exhibit  no  consistent  change  in 
amount  with  increasing  depth.  This  is  true  particularly  of  potassium.  Others 
exhibit  more  or  less  marked  variation  in  amount  at  the  different  levels.  Further- 
more, these  variations  as  a  rule  go  in  certain  general  directions,  and  by  a  careful 
study  of  them  it  is  frequently  possible  to  obtain  clues  as  to  the  age  or  stage  of 
maturity  of  the  various  soils  and  the  nature  of  the  processes  going  on  in  soil 
formation. 

From  this  point  of  view  it  will  be  seen  in  comparing  the  three  strata  with 
each  other  that  all  of  the  soil  types  diminish  rather  rapidly  in  organic  matter 
and  nitrogen  with  increasing  depth,  and  that  this  diminution  is  very  marked 
even  in  the  middle  stratum.  It  should  be  remembered  that  this  stratum,  extend- 
ing to  a  depth  of  20  inches,  includes  in  many  cases  portions  of  the  Aj,  and  even 
of  the  B  horizon,  or  subsoil.  The  sulfur  content  decreases  with  increasing  depth 
in  nearly  all  cases.  This  is  to  be  expected  since  a  portion  of  the  sulfur  exists  in 
combination  with  the  soil  organic  matter,  which  is  more  abundant  in  the  upper 
strata,  and  since  inorganic  forms  of  sulfur  are  not  tenaciously  retained  by  the 
soil  against  the  leaching  action  of  ground  water.  Phosphorus,  on  the  other  hand, 
is  not  removed  from  the  soil  by  leaching.  It  is  converted  by  growing  plants 
into  organic  forms  and  tends  to  accumulate  in  the  surface  soil  in  these  forms  in 


10 


Soil  Report  No.  39 


Soil 
type 
No. 


226] 

426 

926j 

4201 

920( 

4281 

928] 

2601 
460/ 


Table  2. — Plant-Food  Elements  in  the  Soils  of  Logan  County,  Illinois 

Upper  Sampling  Stratum:     About  0  to  Q%  Inches 

Average  pounds  per  acre  in  2  million  pounds  of  soil 


Soil  type 


Total 
organic 
carbon 


Total 
nitro- 
gen 


Total 
phos- 
phorus 


Total 
sulfur 


Total 
potas- 
sium 


Total 
magne- 
sium 


Total 
calcium 


Upland  Prairie  Soils  (200,  400,  900) 


Brown  Silt  Loam. 


Black  Clay  Loam. 


Brown-Gray  Silt  Loam  On 
Tight  Clay 


Brown  Sandy  Loam . 


46  250 
69  970 

33  340 

18  780 


4  410 
6  220 

3  220 
2  100 


1  020 
1  460 

780 
600 


850 
1   120 

680 
440 


35  170 
31  930 

29  440 
27  340 


7  980 
12  490 

4  700 
4  280 


9  820 
18  890 

6  860 
5  920 


Upland  Timber  Soils  (200,  400,  900) 


2341 

434 1- 

934 

235 

435 

935J 

464 

419 


Yellow-Gray  Silt  Loam. 


Yellow  Silt  Loam. 


Yellow-Gray  Sandy  Loam. 
Brown  Clay  Loam 


20  350 

2  080 

860 

570 

35  450 

3  890 

27  480 

2  200 

640 

500 

35  380 

4  320 

10  260 
46  280 

880 
3  900 

480 
1  220 

340 
980 

25  580 
32  520 

3  040 
12  240 

6  680 


8  520 

4  740 
17  160 


Terrace  Soils  (1500) 


1527 
1520 
1566 
1536 
1528 


Brown  Silt  Loam  Over  Sand 

or  Gravel 

Black  Clay  Loam  Over  Sand 

or  Gravel 

Brown  Sandy  Loam  Over  Sand 

or  Gravel 

Yellow-Gray  Silt  Loam  Over 

Sand  or  Gravel 

Brown-Gray  Silt  Loam  On 

Tight  Clay 


47  950 

4  850 

1  360 

680 

31  600 

5  770 

44  720 

5  700 

1  860 

1  100 

37  340 

10  060 

24  120 

2  110 

1  060 

400 

32  250 

4  980 

20  460 

2  460 

900 

400 

35  380 

4  640 

37  340 

3  960 

1  310 

670 

33  840 

4  360 

10  670 

18  540 

7  360 

5  280 

7  600 


Swamp  and  Bottom-Land  Soils  ( 1300,  1400) 


13261 
1426/ 
13201 
1420/ 
13191 
14191 
13541 
14541 


Deep  Brown  Silt  Loam. 

Black  Clay  Ijoam 

Brown  Clay  Loam 

Mixed  Loam' 


48  570 

5  030 

1  640 

840 

38  650 

10  560 

54  700 

5  620 

1  640 

800 

34  140 

9  960 

48  540 

5  500 

1  640 

780 

35  700 

10  140 

15  070 

15  900 

16  460 


LIMESTONE  and  SOIL  ACIDITY.— In  connection  with  these  tabulated  data,  it  should  be 
explained  that  the  figures  for  limestone  content  and  soil  acidity  are  omitted  not  because  of  any 
lack  of  importance  of  these  factors,  but  rather  because  of  the  peculiar  difficulty  of  presenting  in 
the  form  of  numerical  averages  reliable  information  concerning  the  limestone  requirement  for  a 
given  soil  type.  A  general  statement,  however,  will  be  found  concerning  the  lime  requirement  of 
the  respective  soil  types  in  connection  with  the  discussions  which  follow. 

'On  account  of  the  heterogenous  character  of  Mixed  Loam,  chemical  analyses  are  not  included 
for  this  type. 

plant  residues  at  the  expense  of  the  underlying  strata.  The  second  stratum 
(6%  to  20  inches)  furnishes  a  considerable  proportion  of  the  phosphorus  thus 
moved  upward,  as  is  attested  by  the  smaller  amounts  found  by  analysis  in  12  of 


Logan  County 


11 


Table  3. — Plant-Food  Elements  in  the  Soils  of  Logan  County,  Illinois 

Middle  Sampling  Stratum:     About  6%  to  20  Inches 

Average  pounds  per  acre  in  4  million  pounds  of  soil 


Soil 
type 
No. 


Soil  type 


Total 
organic 
carbon 

Total 
nitro- 
gen 

Total 
phos- 
phorus 

Total 
sulfur 

Total 
potas- 
sium 

Total 
magne- 
sium 

Total 
calcium 


Upland  Prairie  Soils  (200,  400,  900) 


226] 
426  !> 
9261 
420\ 

920  r 

428  \ 
928/ 

260  \ 
460/ 


Brown  Silt  Loam. 


Black  Clay  Loam. 


Brown-Gray  Silt  Loam  On 
Tight  Clay 


Brown  Sandy  Loam . 


65  400 

6  490 

1  770 

1  310 

70  010 

19  540 

80  100 

7  550 

2  440 

1  650 

64  770 

26  890 

22  760 

3  000 

1  200 

840 

69  800 

13  560 

35  480 

3  640 

1  160 

960 

56  160 

10  160 

19  910 
35  060 

10  280 
13  520 


Upland  Timber  Soils  (200,  400,  900) 


2341 

4341- 

9341 

235] 

435  !• 

935J 

464 

419 


Yellow-Gray  Silt  Loam . 
Yellow  Silt  Loam 


Yellow-Gray  Sandy  Loam . 
Brown  Clay  Loam 


15  020 

2  040 

1  680 

760 

76  700 

14  700 

23  840 

2  440 

1  840 

680 

71  800 

14  640 

13  880 
52  200 

1  720 
4  920 

1  000 
1  720 

360 
1  280 

52  440 
66  840 

7  000 
24  320 

9  280 


17  240 

11  360 
30  480 


Terrace  Soils  (1500) 


1527 
1520 
1566 
1536 
1528 


Brown  Silt  Loam  Over  Sand 

or  Gravel 

Black  Clay  Loam  Over  Sand 

or  Gravel 

Brown  Sandy  Loam  Over  Sand 

or  Gravel 

Yellow-Gray  Silt  Loam  Over 

Sand  or  Gravel 

Brown-Gray  Silt  Loam  On 

Tight  Clay 


72  950 

7  830 

2  320 

1  130 

66  660 

14  080 

68  400 

6  600 

2  960 

1  520 

67  240 

23  400 

44  160 

4  030 

1  490 

960 

61  900 

11  500 

16  280 

2  160 

1  880 

520 

80  720 

13  080 

27  220 

3  620 

2  100 

780 

71  400 

8  720 

20  750 
34  880 
14  360 
18  080 
13  860 


Swamp  and  Bottom-Land  Soils  (1300,  1400) 


13261 

1426/ 

1320\ 

1420/ 

1319 

1419 

1354 

1454/ 


Deep  Brown  Silt  Loam. 

Black  Clay  Loam 

Brown  Clay  Loam 

Mixed  Loam' 


81  500 

8  860 

2  960 

1  360 

78  700 

23  720 

63  320 

7  520 

2  480 

840 

72  800 

18  680 

57  720 

6  320 

2  640 

1  240 

69  760 

22  080 

29  440 
28  240 

30  400 


LIMESTONE  and  SOIL  ACIDITY.— See  note  in  Table  2. 


'On  account  of  the  heterogeneous  character  of  Mixed  Loam,  chemical  analyses  are  not  in- 
cluded for  this  type. 

the  15  types  in  the  county.     The  analyses  indicate  that  the  lower  stratum  has 
also  contributed  to  some  extent  in  this  upward  movement  of  phosphorus. 

Two  important  basic  elements,  calcium  and  magnesium,  have  undergone 
some  shifting  in  the  different  levels,  as  exhibited  by  analyses  of  upland  types. 
In  the  surface  soil  the  calcium  content,  on  the  whole,  is  much  higher  than  that 
of  magnesium,  indicating  a  more  abundant  supply  of  calcium  in  the  soil-forming 
materials.  In  the  middle  stratum  the  calcium  content  remains  the  same  or 
diminishes  as  compared  with  the  upper.     The  magnesium  content,  on  the  other 


12 


Soil  Report  No.  39 


Table  4. — Plant-Food  Elements  in  the  Soils  of  Logan  County,  Illinois 

Lower  Sampling  Stratum:     About  20  to  40  Inches 

Average  pounds  per  acre  in  6  million  pounds  of  soil 


Soil 
type 

No. 


Soil  type 


Total 
organic 
carbon 


Total 
nitro- 
gen 


Total 
phos- 
phorus 


Total 
sulfur 


Total 
potas- 
sium 


Total 
magne- 
sium 


Total 
calcium 


Upland  Prairie  Soils  (200,  400,  900) 


Brown  Silt  Loam. 


Black  Clav  Loam. 


Brown-Gray  Silt  Loam  On 
Tight  Clay 


Brown  Sandy  Loam . 


42  830 

5  440 

2  330 

1  400 

105  050 

36  870 

46  670 

5  080 

3  170 

1  540 

97  810 

47  600 

18  660 

3  120 

2  820 

1  320 

103  320 

38  640 

36  420 

3  600 

1  740 

660 

84  780 

25  980 

31  400 
76  510 

22  920 
47  700 


Upland  Timber  Soils  (200,  400,  900) 


234 
434 

9341 

235 

435^ 

935J 

464 

419 


Yellow-Gray  Silt  Loam. 
Yellow  Silt  Loam 


Yellow-Gray  Sandy  Loam . 
Brown  Clay  Loam 


14  730 

2  430 

2  970 

870 

110  820 

34  200 

19  080 

2  400 

2  700 

720 

95  940 

23  040 

13  140 
43  020 

1  560 
4  080 

1  560 

2  880 

1  140 
900 

83  280 
100  680 

11  340 
42  600 

24  390 


22  020 

16  140 

46  680 


Terrace  Soils  (1500) 


1527 
1520 
1566 
1536 
1528 


Brown  Silt  Loam  Over  Sand 

or  Gravel 

Black  Clay  Loam  Over  Sand 

or  Gravel 

Brown  Sandy  Loam  Over  Sand 

or  Gravel 

Yellow-Gray  Silt  Loam  Over 

Sand  or  Gravel 

Brown-Gray  Silt  Loam  On 

Tight  Clay 


49  290 

5  430 

3  030 

1  190 

98  490 

26  900 

39  420 

4  560 

3  840 

1  320 

101  520 

39  240 

29  250 

2  860 

1  460 

840 

94  330 

17  740 

17  580 

2  880 

3  420 

900 

117  900 

23  880 

18  570 

3  420 

3  150 

780 

105  600 

21  570 

29  690 
40  980 
19  900 
27  120 
22  740 


Swamp  and  Bottom-Land  Soils  (1300-1400) 


1326 

1420 

1320 

1420 

1319 

1419 

13541 

1454  f 


Deep  Brown  Silt  Loam. 

Black  Clay  Loam 

Brown  Clay  Loam 

Mixed  Loam> 


87  660 

8  520 

3  780 

1  770 

114  120 

32  700 

55  860 

6  120 

3  240 

840 

100  680 

29  520 

41  160 

4  740 

3  360 

1  620 

108  360 

33  660 

42  030 
39  900 
42  360 


LIMESTONE  and  SOIL  ACIDITY.— See  note  in  Table  2. 


^On  account  of  the  heterogeneous  character  of  Mixed  Loam,  chemical  analyses  are  not  in- 
cluded for  this  type. 

hand,  increases  in  both  the  middle  and  lower  strata.  These  two  elements  are 
unequally  removed  from  the  -soil  by  leaching,  the  calcium  being  dissolved  and 
carried  downward  to  a  greater  extent  than  magnesium.  Consequently  the 
magnesium  content  tends  to  become  high  in  the  middle  and  lower  strata,  while 
the  calcium  content  of  the  lower  sampling  strata  is,  on  the  average,  little  or  no 
higher  than  the  upper.  This  spread  between  these  two  elements  in  the  lower 
depths  is  greatest  in  soils  of  extreme  maturity  and  cannot  be  observed  at  all  in 
soils  so  young  as  to  show  indistinct  stratification.    In  line  with  this  idea  it  would 


Logan  County  13 

appear  that  Logan  county  soils  are.  for  the  most  part,  in  youth  and  middle  age, 
none  being  in  extremely  advanced  stages. 

Potassium,  anotlier  important  basic  plant-food  element,  is  present  in  much 
larger  amounts  than  either  calcium  or  magnesium,  and  does  not  exhibit  any 
marked  variation  in  amount  in  the  different  depths.  Wherever  any  differences 
do  occur,  they  are  only  slight  considered  in  ])roportion  to  the  total  amounts 
present. 

It  is  frequently  of  interest  to  know  the  total  supply  of  a  plant-food  element 
accessible  to  the  growing  crops.  While  it  is  not  possible  to  obtain  this  informa- 
tion exactly,  especially  for  the  deeper-rooted  crops,  it  seems  probable  that  prac- 
tically all  of  the  feeding  range  of  the  roots  of  most  of  our  common  field  crops  is 
included  in  the  upper  40  inches  of  soil.  By  adding  together  for  a  given  soil 
type  the  corresponding  figures  in  Tables  2,  3,  and  4,  the  total  amounts  of  the 
respective  plant-food  elements  to  a  depth  of  40  inches  may  be  ascertained. 

Examining  the  data  in  this  manner  the  tables  reveal  that  there  is  not  only 
a  wide  diversity  among  the  different  soils  with  respect  to  a  given  plant-food 
element,  but  that  there  is  also  a  great  variation  with  respect  to  the  relative 
abundance  of  the  various  elements  within  a  given  soil  type  as  measured  by  crop 
requirements.  For  example,  in  one  of  the  most  extensive  soil  types  in  the  county. 
Brown  Silt  Loam,  Upland,  we  find  that  the  total  quantity  of  nitrogen  in  an 
acre  to  a  depth  of  40  inches  amounts  to  16,340  pounds.  This  is  about  the  amount 
of  nitrogen  contained  in  the  same  number  of  bushels  of  corn.  The  amount  of 
phosphorus,  5,120  pounds,  contained  in  the  same  soil  is  equivalent  to  that  con- 
tained in  30,100  bushels  of  corn,  while  in  the  same  quantity  of  this  soil  there  is 
present  210,230  pounds  of  potassium,  the  equivalent  of  that  contained  in  more 
than  one  million  bushels  of  corn.  In  marked  contrast  to  this  soil,  Yellow-Gray 
Silt  Loam,  an  important  upland  timber  soil  type,  contains  in  the  40-  inch  stratum 
less  than  one-half  as  much  nitrogen,  or  6,550  pounds  per  acre,  an  amount  equal 
to  that  in  6,550  bushels  of  corn.  The  phosphorus  content  of  Yellow-Gray  Silt 
Loam  is  slightly  higher  than  that  of  Brown  Silt  Loam,  namely,  5,510  pounds  in 
an  acre,  which  is  equivalent  to  that  contained  in  32,400  bushels  of  corn.  The 
potassium  content  is  about  the  same  as  in  Brown  Silt  Loam. 

In  the  case  of  calcium  the  legumes  utilize  and  remove  from  the  soil  much 
larger  quantities  than  do  the  grain  crops,  and  the  comparisons  will  therefore 
be  of  more  interest  if  one  of  these  crops  is  used.  A  ton  of  red  clover  contains 
approximately  29  pounds  of  calcium,  while  100  bushels  of  corn  contain  only  about 
one  pound  of  this  element.  The  61,130  pounds  of  calcium  in  the  40-inch  depth 
of  Brown  Silt  Loam,  therefore,  are  equivalent  to  that  in  2,100  tons  of  red  clover 
hay,  while  that  in  YelloAv-Gray  Silt  Loam  is  only  two-thirds  as  high,  namely, 
40,350  pounds,  or  the  equivalent  of  1,400  tons  of  the  same  hay. 

It  is  obvious  from  the  above  comparisons  that  the  outstanding  differences 
between  these  two  important  soil  types,  so  far  as  chemical  composition  is  con- 
cerned, lie  in  their  calcium,  nitrogen,  and  organic  matter. 

These  considerations  are  not  intended  to  imply  that  it  is  possible  to  predict 
how  long  it  might  be  before  a  certain  soil  would  become  exhausted  under  a  given 
system  of  cropping.    Neither  do  the  figures  necessarily  indicate  the  immediate 


14  Soil  Report  No.  39 

procedure  to  be  followed  in  the  improvement  of  a  soil,  for  other  factors  enter 
into  consideration,  aside  from  merely  the  amount  of  plant-food  elements  present. 
Much  depends  upon  the  nature  of  the  crops  to  be  grown,  in  their  utilization  of 
plant-food  materials,  and  much  depends  upon  the  availability  of  the  plant-food 
substances.  Finally,  in  planning  the  detailed  procedure  for  the  improvement  of 
a  soil,  there  enter  for  consideration  all  the  economic  factors  involved  in  any 
fertilizer  treatment.  Such  figures,  do,  however,  furnish  an  inventory  of  the  total 
stocks  of  the  plant-food  elements  that  can  possibly  be  drawn  upon,  and  in  this 
way  contribute  fundamental  information  for  the  intelligent  planning,  in  a  broad 
way,  of  systems  of  soil  management  for  conserving  and  improving  the  fertility 
of  the  land. 

DESCRIPTION  OF  SOIL  TYPES 

UPLAND  PRAIRIE  SOILS 

The  upland  prairie  soils  of  Logan  county  occupy  454.86  square  miles,  or 
nearly  three-fourths  of  the  area  of  the  county.  The  dark  color  of  the  prairie 
soils  is  due  to  the  accumulation  of  organic  matter  which  is  derived,  very  largely, 
from  the  fibrous  roots  of  the  prairie  grasses.  The  network  of  grass  roots  which 
once  covered  these  areas  was  protected  from  rapid  and  complete  decay  by  the 
covering  of  fine,  moist  surface  soil  and  by  the  mat  of  vegetative  material  formed 
by  the  debris  of  the  dead  leaves  and  stems.  On  the  native  prairies  the  stems 
and  leaves  were  usually  burned  in  part  by  prairie  fires  or  disappeared  in  part 
by  decay.  This  surface  accumulation,  which  was  constantly  renewed,  added  but 
little  organic  matter  to  the  soil  directly,  but  the  decay  of  the  prairie-grass  roots 
was  retarded  considerably  by  it. 

The  upland  prairie  soils  in  this  county  include  some  areas  of  recent  timber 
growth,  where  certain  kinds  of  trees  have  spread  over  the  prairie,  but  this  fores- 
tation  has  not  been  of  sufficient  duration  to  produce  the  characteristic  timber 
soils.  These  areas  of  greater  or  less  width  are  found  along  the  border  of  most 
timber  tracts,  so  that  the  timber  actually  extended  a  little  farther  than  the  soil 
would  indicate. 

Brown  Silt  Loam  (226,  426,  926) 

Brown  Silt  Loam,  as  it  is  mapped  in  Logan  county,  occupies  nearly  370 
square  miles,  or  about  60  percent  of  the  area  of  the  county.  It  varies  in  character 
depending  on  topography.  Three  divisions  of  the  type  as  mapped  are  recognized 
at  the  present  time.  Each  of  these  is  described  below  so  that  it  may  be  recognized 
in  the  field. 

1.  Light  Brown  Silt  Loam.  This  type  occurs  on  the  higher  areas  and  on 
slopes  where  the  surface  drainage  is  good.  The  A^  horizon,  or  surface,  is  about 
7  inches  thick  and  is  a  light  brown  silt  loam,  frequently  having  a  yellowish  cast. 
The  A,  horizon,  or  subsurface,  extending  to  a  depth  of  about  18  inches,  is  a 
yellowish  brown  silt  loam.  The  B  horizon,  or  upper  subsoil,  is  a  friable,  non- 
mottled,  dark  reddish  yellow  silty  clay  loam.     The  C  horizon,  or  lower  subsoil, 


Logan  County  15 

which  is  found  at  a  depth  of  about  36  inches,  is  a  very  friable,  slightly  mottled 
silt  loam  or  fine  sandy  loam. 

Management. — The  character  of  tlie  profile  of  Light  Brown  Silt  Loam,  to- 
gether with  its  topographic  position,  affords  perfect  surface  and  underdrainage. 
Some  care  must  be  exercised  in  preventing  erosion,  as  many  of  the  slopes  are 
steep  enough  to  allow  rapid  runoff  if  the  surface  is  bare.  This  soil  is  not  as  high 
in  organic  matter  and  nitrogen  as  it  should  be  and  it  is  usually  medium  acid. 
Limestone  should  be  applied  at  the  rate  of  2  to  3  tons  an  acre,  and  clover  grown 
every  3  or  4  years  as  a  source  of  organic  matter  and  nitrogen.  The  best  informa- 
tion available  on  the  treatment  of  this  type  comes  from  the  Mt.  Morris  experi- 
ment field  wliich  is  located  in  part  on  Light  Brown  Silt  Loam.  The  results  from 
this  field  show  a  very  marked  response  to  manure.  Whei-e  limestone  was  applied 
in  addition  to  manure,  a  further  increase  was  secured  which  was  sufficiently 
large  to  pay  a  good  profit  on  the  cost  of  the  limestone.  Another  treatment  which 
gave  very  good  increases  on  this  field  was  residues  and  limestone  used  in  com- 
bination. Potash  has  not  increased  the  yields  on  this  field.  Rock  phosphate  when 
used  in  addition  to  manure  has  not  increased  yields,  and  when  used  in  addition 
to  residues,  the  yields  have  been  increased  just  about  enough  to  pay  for  applying 
half  a  ton  of  rock  phosphate  per  acre  once  in  the  rotation.  For  further  descrip- 
tion of  the  ]\It.  Morris  field,  including  the  data,  see  page  40. 

2.  Brown  Siit  Loam.  This  type  occupies  intermediate  topographic  posi- 
tions. It  differs  from  the  preceding  type,  Light  Brown  Silt  Loam,  in  having  a 
darker  and  usually  thicker  Aj  horizon,  or  surface,  a  less  yellow  Ag  horizon,  or 
subsurface,  and  a  heavier,  less  friable,  and  somewhat  mottled  B  horizon,  or  upper 
subsoil. 

Management. — BroAvn  Silt  Loam  is  somewhat  less  acid  than  Light  Brown 
Silt  Loam  but  requires  limestone  to  grow  alfalfa  or  sweet  clover.  It  was 
originally  well  supplied  with  organic  matter  and  has  been  subject  to  but  little 
loss  of  soil  material  thru  erosion.  The  Kewanee  experiment  field  is  located,  for 
the  most  part,  on  this  soil  type.  A  description  of  the  work  on  this  field,  including 
the  experimental  data,  will  be  found  on  page  42.  Unfortunately,  the  Kewanee 
field  has  several  draws  crossing  the  plots  which  are  a  much  heavier  soil,  so  that 
the  results  from  the  field  cannot  be  applied  to  Brown  Silt  Loam  with  as  much 
confidence  as  would  otherwise  be  the  case.  It  is  almost  certainly  true,  however, 
that  the  presence  of  the  heavier  type  on  the  Kewanee  field  has  the  effect  of 
diminishing  the  increases  due  to  treatment.  This  field  shows  very  good  results 
for  manure  on  corn  and  oats,  but  less  effect  on  wheat.  Limestone  has  given 
profitable  increases,  particularly  in  the  residues  system.  Rock  phosphate  has 
increased  the  yield  of  wheat  on  the  manure  plots  by  5.5  bushels,  but  has  had 
little  or  no  effect  on  the  other  crops  in  the  rotation.  On  the  residues  plots,  rock 
phosphate  has  caused  very  satisfactory  increases  in  the  yield  of  corn,  oats,  and 
wheat,  but  has  had  little  effect  on  the  yield  of  clover  hay.  A,  comparison  of 
rock  and  acid  phosphate  on  the  Kewanee  field,  which  has  been  in  progress  too 
short  a  time  to  allow  final  conclusions,  suggests  that  better  results  might  be 
secured  on  this  soil  type  with  acid  phosphate  than  with  rock  phosphate.     This 


16  Soil  Eeport  No.  39 

tentative  suggestion  is  strengthened  by  the  results  from  the  Bloomington  field 
(see  page  44),  which  is  located  in  part  on  this  soil  type.  Steamed  bone  meal 
has  been  used  as  the  source  of  phosphorus  on  this  field  and  the  increases  caused 
by  its  use  have  been  very  striking.  The  only  concrete  suggestion  for  the  phos- 
phate fertilization  of  this  soil  type  which  can  be  made  at  the  present  time  is  to 
make  a  trial  of  one  of  the  more  available  forms  of  phosphates,  applying  it  for  the 
wheat  crop. 

3.  Brown  Silt  Loam  on  Clay.  This  type  occupies  the  nearly  level  or  only 
gently  sloping  areas  in  the  upland  prairie  region.  It  is  characterized  by  a  dark 
brown  A^  horizon,  or  surface,  about  9  inches  thick  and  a  brown  Ag  horizon,  or 
subsurface,  containing  pale  yellow  spots.  The  B  horizon,  or  upper  subsoil,  is 
usually  a  strongly  mottled,  brownish  yellow,  somewhat  compact  and  plastic, 
clay  loam.  At  a  depth  of  32  to  40  inches,  the  more  friable  C  horizon,  or  lower 
subsoil,  is  found. 

Management. — This  type  is  either  not  acid  or  only  slightly  so.  The  subsoil, 
while  more  compact  and  plastic  than  that  under  either  of  the  preceding  types 
discussed,  drains  well  with  tile.  The  Aledo  experiment  field  is  located  on  Brown 
Silt  Loam  On  Clay  and  the  results  from  this  field  may  be  used  as  a  guide  in  the 
treatment  of  this  soil  type  in  Logan  county.  Manure  has  given  very  good 
returns.  Limestone  has  failed  to  give  very  convincing,  increases  and  its  indis- 
criminate use  could  hardly  be  advised  on  this  soil  unless  alfalfa  or  sweet  clover 
is  to  be  grown.  Rock  phosphate  has  not  caused  increases  in  yield  on  the  manure 
plots  but  its  use  on  the  residues  plots  has  resulted  in  sufficiently  large  increases 
to  justify  advising  its  use  when  manure  is  not  available.  Phosphate  comparisons 
have  been  in  progress  on  the  Aledo  field  since  3916  and  the  reader  is  asked  to 
turn  to  page  45  of  the  Supplement  to  this  Report  and  make  a  study  of  the  results 
as  an  aid  in  solving  his  phosphate  problem  on  Brown  Silt  Loam  On  Clay. 

Black  Clay  Loam  (420,  920) 

Black  Clay  Loam  is  extensively  developed  in  Logan  county,  occupying  all 
told  nearly  84  square  miles,  or  about  131/2  percent  of  the  total  area  of  the 
county.  The  Aj  horizon,  or  surface,  which  is  about  10  inches  thick,  is  black  clay 
loam.  The  A2  horizon,  or  subsurface,  is  9  or  10  inches  thick.  It  is  drabbish 
black  clay  loam.  The  B  horizon,  or  upper  subsoil,  varies  considerably.  In  some 
places  it  is  a  deep  heavy  gray  clay,  and  in  others,  drab  elaj^  resting  on  very  friable 
yellow  fine  sandy  loam.  The  pond,  or  alluvial,  formation  of  this  type  explains  the 
subsoil  variations. 

Management. — Black  Clay  Loam  rarely  needs  limestone  to  grow  sweet  clover. 
Some  areas  of  the  type  contain  sufficient  alkali  to  be  harmful.  It  is  a  productive 
soil  and  needs  no  treatment  other  than  fresh  organic  matter  to  help  keep  it  in 
good  physical  condition.  Clover  should  be  grown  every  third  or  fourth  year  and 
turned  under  directly  or  as  manure.  The  reader  is  asked  to  lurn  to  page  50, 
where  the  results  and  discussion  of  the  Hartsburg  experiment  field,  which  is 
located  on  this  soil  type,  will  be  found. 


I 


Logan  County  17 

Brown-Gray  Silt  Loam  On  Tight  Clay  (428,  928) 

Brown-Gray  Silt  Loam  On  Tight  Clay,  Upland,  is  a  minor  type  in  Logan 
county,  aggregating  only  250  acres.  The  reader  is  referred  to  page  20,  where 
a  description  of  Brown-Gray  Silt  Loam  On  Tight  Clay,  Terrace,  will  be  found. 
The  two  types  as  developed  in  Logan  county  are  identical  except  in  origin. 

Brown  Sandy  Loam  (260,  460) 

Brown  Sandy  Loam  is  a  minor  type  in  Logan  county.  It  occurs  as  small 
areas  in  the  northwestern  part  of  the  county  and  aggregates  only  1.15  square 
miles.  The  dune-like  topography  of  the  region  where  this  type  occurs  suggests 
its  wind  origin  and  the  nearness  of  the  sandy  terrace  on  the  west  also  suggests  the 
same  origin.  The  A^  horizon,  or  surface,  to  a  depth  of  7  or  8  inches  is  a  light 
brown  sandy  loam.  Below  this  depth  the  color  changes  gradually  from  yellowish 
brown  to  yellow  and  the  texture  becomes  coarser.  The  areas  which  have  been 
undisturbed  by  the  wind  for  a  Igng  period  of  time  have  developed  a  finer  texture 
and  some  compaction  in  the  subsoil. 

Management. — The  occurrence  of  this  type  in  small  areas  makes  it  usually 
necessary  to  crop  this  soil  in  the  same  Avay  that  the  adjacent  land  is  cropped. 
It  is  possible,  however,  to  provide  for  larger  additions  of  leguminous  organic 
matter  and  manure  than  are  given  to  the  adjacent  silt  loams  and  clay  loams. 
Limestone  should  be  applied  at  the  rate  of  about  2  tons  an  acre,  and  sweet  clover 
should  be  grown  once  in  the  rotation.  The  sweet  clover  can  well  be  utilized  by 
plowing  it  down  in  the  spring  of  the  second  year  for  corn.  No  mineral  fertilizer 
treatment  is  advised  except  on  a  trial  basis. 

UPLAND  TIMBER  SOILS 

The  upland  timber  soils  are  not  extensively  developed  in  Logan  county. 
They  cover  only  about  42  square  miles,  or  less  than  7  percent  of  the  area  of  the 
county.  They  occur  adjacent  to  most  of  the  streams.  They  are  usually  char- 
acterized by  a  yellow  or  yellowish  gray  color,  which  is  due  to  the  low  organic- 
matter  content.  This  lack  of  organic  matter  has  been  caused  by  the  long-con- 
tinued growth  of  forest  trees.  As  the  forests  invaded  the  prairies,  the  following 
effects  were  produced :  the  shading  of  the  trees  prevented  the  growth  of  grasses, 
the  roots  of  which  are  mainly  responsible  for  the  large  amount  of  organic  matter 
in  the  prairie  soils ;  and  the  trees  themselves  added  very  little  organic  matter 
to  the  soil,  for  the  leaves  and  branches  either  decayed  or  were  destroyed  by  forest 
fires.  The  timbered  soils  are  divided  into  two  groups,  the  undulating  and  the 
eroded. 

Yellow-Gray  Silt  Loam  (234,  434,  934) 

Yellow-Gray  Silt  Loam  as  shown  on  the  soil  map  occurs  most  extensively 
in  the  south-central,  west-central,  and  north-central  parts  of  the  county.  It 
aggregates  a  total  of  about  36  square  miles  and  is  by  far  the  most  important 
light-colored  or  timber  soil  in  the  county.  The  Aj  horizon,  or  surface,  is  a 
brownish  gray  silt  loam  and  varies  from  6  to  8  inches  in  thickness.     The  A, 


18  ,  Soil  Report  No.  39 

horizon,  or  subsurface,  varies  from  6  to  8  or  10  inches  in  thickness  and  is  a 
yellowish  gray  or  grayish  brown  silt  loam.  The  B  horizon,  or  upper  subsoil, 
varies  in  compactness,  color,  and  thickness.  In  the  rolling  areas  it  is  reddish 
brown,  in  the  fiat  areas,  drabbish,  and  on  intermediate  topography  it  is  pale 
yellow  with  gray  mottling. 

Management. — In  the  above  description  of  Yellow-Gray  Silt  Loam  no  at- 
tempt was  made  to  describe  the  different  kinds  of  Yellow-Gray  Silt  Loam  which 
occur  in  Logan  county  and  to  point  out  their  correlation  with  topography.  In 
planning  the  management  of  this  type,  however,  attention  should  be  paid  to 
differences  in  the  type,  particularly  with  reference  to  the  subsoil.  The  rolling 
areas  have  a  pervious  subsoil  but  because  of  their  topography  are  subject  to 
erosion.  They  should  be  cropped  in  such  a  way  as  to  have  a  vegetative  cover  on 
the  land  as  much  of  the  time  as  possible.  The  more  gentle  slopes  have  a  less 
pervious  subsoil  but  are  not  subject  to  serious  erosion  if  reasonable  care  is  taken 
to  control  it.  The  flat  areas  have  a  relatively  impervious  subsoil,  tho  not  so  im- 
pervious that  tile  will  not  draw.  Drainage  of  these  flat  areas,  however,  must  be 
effected  in  part  by  surface  ditches  and  open  furrows.  The  type  as  a  whole  is  acid 
and  limestone  should  be  applied.  The  flat  areas  are  usually  more  acid  than  the 
rolling  ones.  All  phases  of  the  type  are  low  in  nitrogen  and  organic  matter. 
These  constituents  should  be  secured  by  growing  clover,  preferably  sweet  clover, 
and  plowing  it  down  in  the  spring  of  the  second  year  for  corn.  No  experiment 
field  data  are  available  upon  which  to  base  fertilizer  recommendations,  but  it  is 
suggested  that  one  or  more  of  the  phosphates  be  tried,  particularly  for  the 
wheat  crop.     See  "The  Phosphorus  Problem,"  page  32. 

Yellow  Silt  Loam  (235,  435,  935) 

Yellow  Silt  Loam  is  a  minor  type  in  Logan  county  because  of  its  small  total 
acreage,  less  than  6  square  miles,  and  because  of  its  relatively  low  agricultural 
value.  The  character  of  this  type  varies,  depending  largely  on  the  rapidity  of 
erosion.  In  places  a  shallow  surface  soil  has  been  developed,  while  in  other 
places  the  removal  of  the  soil  material  by  erosion  is  more  rapid  than  the  de- 
velopment of  the  soil  horizons. 

Management. — Yellow  Silt  Loam  should,  for  the  most  part,  be  used  for 
permanent  pasture,  orchard,  or  timber.  There  are  areas  having  a  slope  suffi- 
ciently gentle  to  be  farmed  successfully  if  care  is  taken  to  reduce  erosion  to  the 
minimum.  A  very  good  use  to  make  of  the  less  steep  slopes  is  to  seed  alfalfa 
after  applying  limestone.  If  the  alfalfa  is  preceded  by  sweet  clover,  little 
difficulty  should  be  encountered  in  getting  a  stand. 

Yellow-Gray  Sandy  Loam  (464) 

Yellow-Gray  Sandy  Loam  is  a  very  minor  tj^pe  in  Logan  county,  totaling 
less  than  a  hundred  acres.  It  may  be  handled  in  the  same  way  as  Brown  Sandy 
Loam  (see  page  17). 


Logan  County  19 

Brown  Clay  Loam  (419) 

Brown  Clay  Loam,  Upland,  is  a  shallow  lake  or  pond  formation.  The 
moisture  conditions  during  its  development  have  been  such  that  the  organic 
matter  has  decayed  without  the  formation  of  Jhe  black  pigments ;  consequently 
a  brown  rather  than  a  black  soil  has  resulted.  There  are  about  250  acres  of 
Brown  Clay  Loam  in  the  upland  in  Logan  county. 

The  Aj  horizon,  or  surface,  is  about  8  inches  thick  and  is  a  brown  clay 
loam.  The  A^  horizon,  or  subsurface,  extends  to  a  depth  of  about  19  inches  and 
is  a  drabbish  brown  clay  loam.  The  B  horizon,  or  upper  subsoil,  is  a  medium 
compact,  medium  plastic,  brownish  drab  clay  loam.  It  contains  many  pale 
yellow  and  reddish  brown  spots.  The  C  horizon,  or  lower  subsoil,  is  a  medium 
friable,  drab  and  pale  yellow  clay  loam. 

Managemeni. — This  .soil  should  be  handled  in  the  same  way  as  Black  Clay 
Loam,  Upland  (see  page  16).  It  is  a  productive  soil  and,  so  far  as  is  known, 
does  not  contain  alkali  in  harmful  amounts. 

TERRACE  SOILS 

Relatively  small  areas  of  terrace  soils  occur  in  Logan  county.  These  soils 
were  formed  in  remote  times  by  overloaded  and  flooded  streams  which  deposited 
an  immense  amount  of  material  in  the  old  channels.  Later  as  the  streams 
diminished  in  size  or  cut  their  channels  deeper,  new  bottoms  were  developed, 
leaving  the  old  flood  plains  above  overflow,  thus  forming  terraces. 

These  terrace  formations  which  were  built  up,  for  the  most  part,  during  and 
immediately  following  the  Glacial  period,  were  later  covered  to  varying  depths 
with  wind-blown  material  from  which  the  present  soils  were  formed. 

Brown  Silt  Loam  Over  Sand  or  Gravel  (1527) 

Brown  Silt  Loam  Over  Sand  or  Gravel  is  the  most  important  terrace  type 
in  Logan  county.  It  covers  a  little  over  38  square  miles  and  is  a  productive 
soil.  It  is  very  similar  to  Brown  Silt  Loam  On  Clay,  Upland,  except  in  origin. 
See  page  16  for  the  description  of  that  type  and  for  suggestions  regarding  its 
management. 

Black  Clay  Loam  Over  Sand  or  Gravel  (1520) 

Black  Clay  Loam  Over  Sand  or  Gravel  occupies  a  little  over  4  square  miles 
in  Logan  county.  It  differs  in  no  essential,  except  in  origin,  from  Black  Clay 
Loam,  Upland.  See  page  16  for  a  description  of  that  type  and  for  suggestions 
regarding  its  management. 

Brown  Sandy  Loam  Over  Sand  or  Gravel  (1566) 

Brown  Sandy  Loam  Over  Sand  or  Gravel  is  a  minor  type  in  Logan  county, 
occupying  only  one-third  of  a  square  mile.  It  is  very  similar  to  Brown  Sandy 
Loam,  Upland,  except  in  origin,  and  the  reader  is  asked  to  turn  to  the  discussion 
of  that  type,  page  17. 


20  Soil  Report  No.  39 

Yellow-Gray  Silt  Loam  Over  Sand  or  Gravel  (1536) 

Yellow-Gray  Silt  Loam  Over  Sand  or  Gravel  is  similar  to  the  flat  Yellow- 
Gray  Silt  Loam,  Upland.  The  underlying  sand  or  gravel  is  sufficiently  deep  not 
to  cause  a  drouthy  condition,  and  yet  its  presence  improves  the  underdrainage. 
Limestone  should  be  supplied  and  clover  grown  as  is  suggested  for  Yellow-Gray 
Silt  Loam,  Upland  (page  17). 

Brown-Gray  Silt  Loam  On  Tight  Clay  (1528) 

Brown-Gray  Silt  Loam  On  Tight  Clay,  Terrace,  occurs  for  the  most  part 
along  Deer  creek  northwest  of  the  village  of  Beason.  It  occupies  a  total  of  5.72 
square  miles  in  Logan  county.  It  is  important  to  note  the  characteristics  of  this 
type  carefully,  as  it  resembles  Brown  Silt  Loam,  Terrace,  very  closely  in  the 
surface  and  is  often  mistaken  for  it. 

The  A^  horizon,  or  surface,  to  a  depth  of  8  or  9  inches  is  a  grayish  brown 
silt  loam  which  may  entirely  lose  its  gray  cast  when  moist.  The  A^  horizon,  or 
subsurface,  is  gray  silt  loam  and  extends  to  a  depth  of  18  or  20  inches.  Imme- 
diately below  the  gray  subsurface  layer  or  horizon,  the  plastic,  heavily  mottled 
tight  clay  B  horizon,  or  upper  subsoil,  is  found.  This  horizon  extends  to  a  depth 
of  about  36  inches  and  rests  on  a  gray,  more  friable,  C  horizon.  Some  areas  of  this 
type  do  not  correspond  to  the  above  description  in  that  the  tight  clay  horizon  is 
much  deeper  because  of  silting  in.  These  deeper  areas,  while  not  separated  out 
on  the  map,  are  better  soil  because  of  the  greater  depth  of  the  tight  clay. 

Management.— Brovfn-Gray  Silt  Loam,  Terrace,  varies  in  its  need  for  lime, 
some  areas  showing  no  acidity  at  all,  while  others  need  2  to  3  tons  of  limestone 
an  acre.  Before  applying  limestone,  each  field  should  be  tested  in  detail  with 
the  assistance  of  the  county  farm  adviser  or  the  Agricultural  Experiment  Station. 
Underdrainage  is  not  effective  on  this  type  except  on  the  areas  in  which  the  tight 
clay  lies  below  the  depth  at  which  the  tile  are  placed.  Surplus  water  must  be 
removed  by  open  furrows  and  ditches.  Sweet  clover  grows  well  on  this  soil  and 
improves  very  materially  the  grain  crops  that  follow  it.  No  fertilizer  applica- 
tions, except  manure,  are  advised  for  this  type  until  the  nitrogen  and  organic- 
matter  contents  of  the  soil  are  increased  by  means  of  legumes. 

SWAMP  AND  BOTTOM-LAND  SOILS 

This  group  includes  the  bottom  lands  along  the  creeks  of  the  county.  These 
bottoms  were  formed  at  a  time  when  the  creeks  carried  much  more  water  than 
they  do  at  the  present  time.  Much  of  this  land  is  subject  to  overflow.  On  the 
soil  map,  the  Swamp  and  Bottom-Land  Soils  are  divided  into  two  groups  but 
these  groups  are  combined  into  one  in  the  following  descriptions  for  the  reason 
explained  on  page  4. 

Deep  Brown  Silt  Loam  (1326,  1426) 

Deep  Brown  Silt  Loam  is  a  productive  soil,  easily  worked,  and  where  sub- 
ject to  overflow  is  non-acid.  It  is  a  young,  immature  soil,  and  has  not  developed 
distinct  horizons.     The  surface  is  a  brown  to  dark  brown  silt  loam,  frequently 


Logan  County  21 

16  or  even  18  inches  thick.  Below  this  dark-colored  surface,  the  color  gradually 
assumes  a  drabbish  cast  with  increasing  depth.  Often  at  a  depth  of  36  to  40 
inches  it  becomes  gray,  showing  a  high  water  table. 

Mnriagement. — Deep  Brown  Silt  Loam  requires  no  fertilizer  treatment  other 
than  the  plowing  down  of  legumes,  particularly  on  the  non-overflow  areas,  and 
the  use  of  limestone  where  acidity  has  developed. 

Black  Clay  Loam  (1320,  1420) 

A  total  of  12  square  miles  of  Black  Clay  Loam,  Bottom,  occurs  in  Logan 
county.  It  is  found  in  situations  where  the  rate  of  flow  of  the  sediment-carrying 
current  was  so  slow  that  only  fine  particles  could  be  carried  and  deposited.  The 
surface  is  black  clay  loam,  averaging  about  10  inches  thick.  The  subsurface  and 
subsoil  are  not  distinctly  developed  because  of  the  youth  or  immaturity  of  the 
soil.  Below  10  inches  the  color  becomes  intensely  drab  and  changes  to  gray  or 
grayish  drab  at  about  26  inches. 

Management. — Black  Clay  Loam,  Bottom,  is  productive  but  rather  difficult  to 
Avork  because  of  its  fine  texture.  Fresh  organic  matter  should  be  plowed  down  fre- 
quently to  keep  the  soil  in  a  workable  condition.    Limestone  is  usually  not  needed. 

Brown  Clay  Loam  (1319,  1419) 

Brown  Clay  Loam,  Bottom,  occurs  in  the  southern  part  of  the  county  along 
Lake  fork  of  Salt  creek.  The  reason  for  its  development  rather  than  the  de- 
velopment of  Black  Clay  Loam  is  not  clear.  The  surface  soil  to  a  depth  of  about 
12  inches  is  a  brown  clay  loam.  The  subsurface  and  subsoil  horizons  are  not  well 
defined  because  of  the  youth  of  the  soil.  The  subsurface  is  a  drabbih  brown  clay 
loam  and  extends  to  a  depth  of  about  20  inches.  Tlie  sul)soil  is  a  drab  clay  loam 
with  reddish  brown  spots  and  is  medium  plastic  and  compact.  No  change  in  the 
character  of  the  subsoil  is  apparent  within  the  40-inch  section. 

Management. — Brown  Clay  Loam,  Bottom,  is  a  productive  soil,  easier  to 
work  than  Black  Clay  Loam,  Bottom,  and  for  the  present  needs  nothing  more 
than  the  plowing  down  of  fresh  organic  matter  at  frequent  intervals,  together 
with  improvement  in  drainage. 

Mixed  Loam  (1354,  1454) 

Mixed  Loam,  Bottom,  is  of  alluvial  origin  and  is  very  diverse  in  character. 
It  consists  of  distinct  tj^pes  occurring  in  such  small  areas  that  they  cannot  be 
shown  on  the  map  and  consequently  they  are  all  grouped  together  and  called 
Mixed  Loam.  The  texture  of  the  surface  varies  from  a  sandy  loam  to  a  clay 
loam.  The  subsurface  and  subsoil  vary  in  the  same  way  as  does  the  surface. 
There  are  a  little  more  than  7  square  miles  of  Mixed  Loam  in  this  county. 

Management. — The  diversity  of  Mixed  Loam  calls  for  different  tillage 
methods  where  the  extremes  in  the  type  occur.  Some  areas  are  so  heavy  as  to 
require  care  in  working  them  at  the  right  moisture  content,  while  others  are  very 
sandy.  The  type  in  general  is  not  acid  and  needs  only  fresh  organic  matter  and 
intelligent  tillage. 


APPENDIX 

EXPLANATIONS  FOR  INTERPRETING  THE  SOIL  SURVEY 

CLASSIFICATION  OF  SOILS 

In  order  to  interpret  the  soil  map  intelligently,  the  reader  must  understand 
something  of  the  method  of  soil  classification  upon  which  the  survey  is  based. 
Without  going  far  into  details  the  following  paragraphs  are  intended  to  furnish 
a  brief  explanation  of  the  general  plan  of  classification  used. 

The  soil  type  is  the  unit  of  classification.  Each  type  has  definite  character- 
istics upon  which  its  separation  from  other  types  is  based.  These  characteristics 
are  inherent  in  the  strata,  or  "horizons,"  which  constitute  the  soil  profile  in  all 
mature  soils.  Among  them  may  be  mentioned  color,  structure,  texture,  and 
chemical  composition.  Other  items,  such  as  native  vegetation  (whether  timber 
or  prairie),  topography,  and  geological  origin  and  formation,  may  assist  in  the 
differentiation  of  types,  altho  they  are  not  fundamental  to  it. 

Since  some  of  the  terms  used  in  designating  the  factors  which  are  taken  into 
account  in  establishing  soil  types  are  technical  in  nature,  the  following  definitions 
are  introduced : 

Horizon.  A  layer  or  stratum  of  soil  which  differs  diseernibly  from  those  adjacent  in 
color,  texture,  structure,  chemical  composition,  or  a  combination  of  these  characteristics,  is 
called  an  horizon.  In  describing  a  matured  soil,  three  horizons  designated  as  A,  B,  and  C 
are  usually  considered. 

A  designates  the  upper  horizon  and,  as  developed  under  the  conditions  of  a  humid,  tem- 
perate climate,  represents  the  layer  of  extraction  or  eluviation ;  that  is  to  say,  material  in 
solution  or  in  suspension  has  passed  out  of  this  zone  thru  the  processes  of  weathering. 

B  represents  the  layer  of  concentration  or  illuviation ;  that  is,  the  layer  developed  as  a 
result  of  the  accumulation  of  material  thru  the  downward  movement  of  water  from  the  A 
horizon. 

C  designates  the  layer  lying  below  the  B  horizon  and  in  which  the  material  has  been  less 
affected  by  the  weathering  processes. 

Frequently  differences  within  a  stratum  or  zone  are  discernible,  in  which  case  it  is 
subdivided  and  described  under  such  designations  as  Aj,  and  Aj,  B,,  and  B2,  etc. 

Soil  Profile.     The  soil  section  as  a  whole  is  spoken  of  as  the  soil  profile. 

Depth  and  Thickness.  The  horizons  or  layers  which  make  up  the  soil  profile  vary  in 
depth  and  thickness.  These  variations  are  distinguishing  features  in  the  separation  of  soils 
into  types. 

Physical  Composition.  The  physical  composition,  sometimes  referred  to  as  "texture," 
is  a  most  important  feature  in  characterizing  a  soil.  The  texture  depends  upon  the  relative 
proportions  of  the  following  physical  constituents:  clay,  silt,  fine  sand,  sand,  gravel,  stones, 
and  organic  material. 

Structure.  The  term  "structure"  has  reference  to  the  aggregation  of  particles  within 
the  soil  mass  and  carries  such  qualifying  terms  as  open,  granular,  compact,  columnar, 
laminated. 

Organic-Matter  Content.  The  organic  matter  of  soil  is  derived  largely  from  plant  tissue 
and  it  exists  in  a  more  or  less  advanced  stage  of  decomposition.  Organic  matter  forms  the 
predominating  constituent  in  certain  soils  of  swampy  formation. 

Color,  Color  is  determined  to  a  large  extent  by  the  proportion  of  organic  matter,  but 
.  at  the  same  time  it  is  modified  by  the  mineral  constituents,  especially  by  iron  compounds. 

Reaction.  The  term  "reaction"  refers  to  the  chemical  state  of  the  soil  with  respect 
to  acid  or  alkaline  condition.  It  also  involves  the  idea  of  degree,  as  strongly  acid  or  strongly 
alkaline. 

Carbonate  Content.  The  carbonate  content  has  reference  to  the  calcium  carbonate 
(limestone)  present,  which  in  some  cases  may  be  associated  with  magnesium  or  other  car- 
bonates. The  depth  at  which  carbonates  are  found  may  become  a  very  important  factor 
in  determining  the  soil  type. 

Topography.    Topography  has  reference  to  the  lay  of  the  land,  as  level,  rolling,  hilly,  etc. 

22 


Logan  County  23 

Native  Vegetation.  The  vegetation  or  plant  growth  before  being  disturbed  by  man,  as 
prairie  grasses  and  forest  trees,  is  a  feature  frequently  recognized  in  differentiating  soil  types. 

Geological  Origin.  Geological  origin  involves  the  idea  of  character  of  rock  materials 
composing  the  soil  as  well  as  the  method  of  formation  of  the  soil  material. 

Not  infrequently  areas  are  encountered  in  which  type  characters  are  not 
distinctly  developed  or  in  which  they  show  considerable  variation.  When  these 
variations  are  considered  to  have  sufficient  significance,  type  separations  are  made 
whenever  the  areas  involved  are  sufficiently  large.  Because  of  the  almost  infinite 
variability  occurring  in  soils,  one  of  the  exacting  tasks  of  the  soil  surveyor  is  to 
determine  the  degree  of  variation  which  is  allowable  for  any  given  type. 

Classifying  Soil  Types. — In  the  system  of  classification  used,  the  types  fall 
first  into  four  general  groups  based  upon  their  geological  relationships ;  namely, 
upland,  terrace,  swamp  and  bottom  land,  and  residual.  These  groups  may  be 
subdivided  into  prairie  soils  and  timber  soils,  altho  as  a  matter  of  fact  this  sub- 
division is  applied  in  the  main  only  to  the  upland  group.  These  terms  are  all 
explained  in  the  foregoing  part  of  this  report  in  connection  with  the  description 
of  the  particular  soil  types. 

Naming  and  Numhering  Soil  Types.- — In  the  Illinois  soil  survey  a  system  of 
nomenclature  is  used  which  is  intended  to  make  the  type  name  convey  some  idea 
of  the  nature  of  the  soil.  Thus  the  name  "Yellow-Gray  Silt  Loam"  carries  in 
itself  a  more  or  less  definite  description  of  the  type.  It  should  not  be  assumed, 
however,  that  this  system  of  nomenclature  makes  it  possible  to  devise  type  names 
which  are  adequately  descriptive,  because  the  profile  of  mature  soils  is  usually 
made  up  of  three  or  more  horizons  and  it  is  impossible  to  describe  each  horizon 
in  the  type  name.  The  color  and  texture  of  the  surface  soil  are  usually  included 
in  the  type  name  and  when  material  such  as  sand,  gravel,  or  rock  lies  at  a  depth 
of  less  than  30  inches,  the  fact  is  indicated  by  the  word  ' '  On, ' '  and  when  its  depth 
exceeds  30  inches,  by  the  word  "Over";  for  example.  Brown  Silt  Loam  On 
Gravel,  and  Brown  Silt  Loam  Over  Gravel. 

As  a  further  step  in  systematizing  the  listing  of  the  soils  of  Illinois,  recog- 
nition is  given  to  the  location  of  the  types  with  respect  to  the  geological  areas 
in  which  they  occur.  According  to  a  geological  survey  made  many  years  ago, 
the  state  has  been  divided  into  seventeen  areas  with  respect  to  geological  forma- 
tion and,  for  the  purposes  of  the  soil  survey,  each  of  these  areas  has  been  assigned 
an  index  number.  The  names  of  the  areas  together  with  their  general  location 
and  their  corresponding  index  numbers  are  given  in  the  following  list. 

000     Besidual,  soils  formed  in  place  thru  disintegration  of  rocks,  and  also  rock  outcrop 

100     Unglaciated,  including  three  areas,  the  largest  being  in  the  south  end  of  the  state 

200     Illinoisan  moraines,  including  the  moraines  of  the  Illinoisan  glaciations 

300     Lower  Illinoisan  gladation,  formerly  considered  as  covering  nearly  the  south  third  of  the 

state 
400     Middle  Illinoisan  gladation,  covering  about  a  dozen  counties  in  the  west-central  part  of 

the  state 
500     Upper  Illinoisan  gladation,  covering  about  fourteen  counties  northwest  of  the  middle 

Illinoisan  glaciation 
600     Pre-Iowan  gladation,  but  now  believed  to  be  part  of  the  upper  Illinoisan 
700     lowan  gladation,  lying  in  the  central  northern  end  of  the  state 
800     Deep  loess  areas,  including  a  zone  a  few  miles  wide  along  the  Wabash,  Illinois,  and 

Mississippi  rivers 
900     Early  Wisconsin  moraines,  including  the  moraines  of  the  early  "Wisconsin  glaciation 
1000     Late  Wisconsin  moraines,  including  the  moraines  of  the  late  Wisconsin  glaciation 


24  Soil  Report  No.  39:    Appendix 

1100     Early  Wisconsin  glaciation,  covering  the  greater  part  of  the  northeast  quarter  of  the 

state 
1200     Late  Wisconsin  glaciation,  lying  in  the  northeast  corner  of  the  state 
1300     Old  river-bottom  and  sioamp  lands,  formed  by  material  derived  from  the  lUinoisan  or 

older  glaciations 
1400     Late  river-bottom  and  swamp  lands,  formed  by  material  derived  from  the  Wisconsin  and 

lowan  glaciations 
1500     Terraces,  bench  or  second  bottom  lands,  and  gravel  outvvash  plains 
1600     Lacustrine  deposits,  formed  by  Lake  Chicago,  the  enlarged  glacial  Lake  Michigan 

Further  information  regarding  these  geological  areas  is  given  in  connection 
with  the  general  map  mentioned  above  and  published  in  Bulletin  123  (1908). 

Another  set  of  index  numbers  is  assigned  to  the  classes  of  soils  as  based 

upon  physical  composition.    The  following  list  contains  the  names  of  these  classes 

with  their  corresponding  index  numbers. 

Index  Number  Limits  Class  Names 

0  to     9 Peats 

10  to  12 Peaty  loams 

13  to  14 Mucks 

15  to  19 Clays 

20  to  24 Clay  loams 

25  to  49 Silt  loams 

50  to  59 Loams 

'        60  to  79 Sandy  loams 

80  to  89 Sands 

90  to  94 Gravelly  loams 

95  to  97 Gravels 

98  Stony  loams 

99   Rock  outcrop 

As  a  convenient  means  of  designating  types  and  their  location  with  respect 
to  the  geological  areas  of  the  state,  each  type  is  given  a  number  made  up  of  a 
combination  of  the  index  numbers  explained  above.  This  number  indicates  the 
type  and  the  geological  area  in  which  it  occurs.  The  geological  area  is  always 
indicated  by  the  digits  of  the  order  of  hundreds  while  the  balance  of  the  number 
designates  the  type.  To  illustrate:  the  number  1126  means  Brown  Silt  Loam 
in  the  early  "Wisconsin  glaciation,  434  means  Yellow-Gray  Silt  Loam  of  the  middle 
Illinoisan  glaciation.  These  numbers  are  especially  useful  in  designating  very 
small  areas  on  the  map  and  as  a  check  in  reading  the  colors. 

A  complete  list  of  the  soil  types  occurring  in  each  county,  along  with  their 
corresponding  type  numbers  and  the  area  covered  by  each  type,  will  be  found 
in  the  respective  county  soil  reports  in  connection  with  the  maps. 

SOIL  SURVEY  METHODS 

Mapping  of  Soil  Types. — In  conducting  the  soil  survey,  the  county  consti- 
tutes the  unit  of  working  area.  The  field  work  is  done  by  parties  of  two  to  four 
men  each.  The  field  season  extends  from  early  in  April  to  Thanksgiving.  Dur- 
ing the  winter  months  the  men  are  engaged  in  preparing  a  copy  of  the  soil  map 
to  be  sent  to  the  lithographer,  a  copy  for  the  use  of  the  county  farm  adviser  until 
the  printed  map  is  available,  and  a  third  copy  for  use  in  the  office  in  order  to 
preserve  the  original  official  map  in  good  condition. 

An  accurate  base  map  for  field  use  is  necessary  for  soil  mapping.  These 
maps  are  prepared  on  a  scale  of  one  inch  to  the  mile,  the  official  data  of  the 
original  or  subsequent  land  survey  being  used  as  the  basis  in  their  construction. 


Logan  County  25 

Each  surveyor  is  provided  with  one  of  these  base  maps,  which  he  carries  with 
him  in  the  field ;  and  the  soil  type  boundaries,  together  with  the  streams,  roads, 
railroads,  canals,  town  sites,  and  rock  and  gravel  quarries  are  placed  in  their 
proper  location  upon  the  map  while  the  mapper  is  on  the  area.  With  the  rapid 
development  of  road  improvement  during  the  i)ast  few  years,  it  is  almost  in- 
evitable that  some  recently  established  roads  will  not  appear  on  the  published 
soil  map.  Similarly,  changes  in  other  artificial  features  will  occasionally  occur 
in  the  interim  between  the  preparation  of  the  map  and  its  publication.  The 
detail  or  minimum  size  of  areas  which  are  shown  on  the  map  varies  somewhat, 
but  in  general  a  soil  type  if  less  than  five  acres  in  extent  is  not  shown. 

A  soil  auger  is  carried  by  each  man  with  which  he  can  examine  the  soil  to 
a  depth  of  40  inches.  An  extension  for  making  the  auger  80  inches  long  is  taken 
by  each  party,  so  that  the  deeper  subsoil  may  be  studied.  Each  man  carries  a 
compass  to  aid  in  keeping  directions.  Distances  along  roads  are  measured  by 
a  speedometer  or  other  measuring  device,  while  distances  in  the  field  away  from 
the  roads  are  measured  by  pacing. 

Sampling  for  Analysis. — After  all  the  soil  types  of  a  county  have  been  located 
and  mapped,  samples  representative  of  the  different  types  are  collected  for 
chemical  analysis.  The  samples  for  this  purpose  are  usually  taken  in  three 
depths;  namely,  0  to  6%  inches,  6%  to  20  inches,  and  20  to  40  inches,  as  explained 
in  connection  with  the  discussion  of  the  analytical  data  on  page  6. 

PRINCIPLES  OF  SOIL  FERTILITY 

Probably  no  agricultural  fact  is  more  generally  known  by  farmers  and  land- 
owners than  that  soils  differ  in  productive  power.  A  fact  of  equal  importance, 
not  so  generally  recognized,  is  that  they  also  differ  in  other  characteristics  such 
as  response  to  fertilizer  treatment  and  to  management. 

The  soil  is  a  dynamic,  ever-changing,  exceedingly  complex  substance  made 
up  of  organic  and  inorganic  materials  and  teeming  with  life  in  the  form  of 
microorganisms.  Because  of  these  characteristics,  the  soil  cannot  be  considered 
as  a  reservoir  into  which  a  given  quantity  of  an  element  or  elements  of  plant 
food  can  be  poured  with  the  assurance  that  it  will  respond  with  a  given  increase 
in  crop  yield.  In  a  similar  manner  it  cannot  be  expected  to  respond  with  per- 
fect uniformity  to  a  given  set  of  management  standards.  To  be  productive  a  soil 
must  be  in  such  condition  physically  with  respect  to  structure  and  moisture  as 
to  encourage  root  development ;  and  in  such  condition  chemically  that  injurious 
substances  are  not  present  in  harmful  amounts,  that  a  sufficient  supply  of  the 
elements  of  plant  food  become  available  or  usable  during  the  growing  season, 
and  that  lime  materials  are  present  in  sufficient  abundance  favorable  for  the 
growth  of  the  higher  plants  and  of  the  beneficial  microorganisms.  Good  soil 
management  under  humid  conditions  involves  the  adoption  of  those  tillage,  crop- 
ping, and  fertilizer  treatment  methods  which  will  result  in  profitable  and  per- 
manent crop  production  on  the  soil  type  concerned. 

The  following  paragraphs  are  intended  to  state  in  a  brief  way  some  of  the 
principles  of  soil  management  and  treatment  which  are  fundamental  to  profitable 
and  continued  productivity. 


26 


Soil  Report  No.  39:    Appendix 


CROP  REQUIREMENTS  WITH  RESPECT  TO  PLANT-FOOD  MATERIALS 

Ten  of  the  chemical  elements  are  known  to  be  essential  for  the  growth  of 
the  higher  plants.  These  are  carton,  hydrogen,  oxygen,  nitrogen,  phosphorus, 
sulfur,  potassium,  calcium,  magnesium,  and  iron.  Other  elements  are  absorbed 
from  the  soil  by  growing  plants,  including  manganese,  silicon,  sodium,  aluminum, 
ehlorin,  and  boron.  It  is  probable  that  these  latter  elements  are  present  in 
plants  for  the  most  part,  not  because  they  are  required,  but  because  they  are 
dissolved  in  the  soil  water  and  the  plant  has  no  means  of  preventing  their 
entrance.  There  is  some  evidence,  however,  which  indicates  that  certain  of  these 
elements,  notably  manganese,  silicon,  and  boron,  may  be  either  essential  but 
required  in  only  minute  quantities,  or  very  beneficial  to  plant  growth  under 
certain  conditions,  even  tho  not  essential.  Thus,  for  example,  manganese  has 
produced  marked  increases  in  crop  yields  on  heavily  limed  soils.  Sodium  also 
has  been  found  capable  of  partially  replacing  potassium  in  case  of  a  shortage 
of  the  latter  element. 

Table  5. — Plant-Food  Elements  in  Common  Farm  Crops' 


Produce 

Nitrogen 

Phos- 
phorus 

Sulfur 

Potas- 
sium 

Magne- 
sium 

Calcium 

Iron 

Kind 

Amount 

Wheat,  grain 

Wheat  straw 

Corn,  grain 

Corn  stover 

Corn  cobs 

1  bu. 
1  ton 

1  bu. 
1  ton 
1  ton 

1  bu. 
1  ton 

1  bu. 
1  ton 

1  bu. 
1  ton 

1  ton 

lbs. 
1.42 
10.00 

1.00 

16.00 

4.00 

.66 
12.40 

1.75 
40.00 

3.22 
43.40 

52.08 

lbs. 

.24 
1.60 

.17 
2.00 

.11 
2.00 

.50 
5.00 

.39 
4.74 

4.76 

lbs. 

.10 
2.80 

.08 
2.42 

.06 
4.14 

'3.28 

.27 
5.18 

5.96 

lbs. 

.26 
18.00 

.19 

17.33 

4.00 

.16 
20.80 

.75 
30.00 

1.26 
35.48 

16.64 

lbs. 

.08 
1.60 

.07 
3.33 

.04 
2.80 

.25 

7.75 

.15 
13.84 

8.00 

lbs. 

.02 
3.80 

.01 
7.00 

.02 
6.00 

.13 
29.25 

.14 
27.56 

22.26 

lbs. 
.01 
.60 

.01 
1.60 

Oats,  grain 

Oat  straw 

.01 
1.12 

Clover  seed 

Clover  hay 

Soybean  seed 

Soybean  hay 

Alfalfa  hay 

"i.'oo 

'These  data  are  brought  together  from  various  sources.  Some  allowance  must  be  made  for 
the  exactness  of  the  figures  because  samples  representing  the  same  kind  of  crop  or  the  same  kind 
of  material  frequently  exhibit  considerable  variation. 

Table  5  shows  the  requirements  of  some  of  our  most  common  field  crops  with 
respect  to  seven  important  plant-food  elements  furnished  by  the  soil.  The 
figures  show  the  weight  in  pounds  of  the  various  elements  contained  in  a  bushel 
or  in  a  ton,  as  the  case  may  be.  From  these  data  the  amount  of  an  element  re- 
moved from  an  acre  of  land  by  a  crop  of  a  given  yield  can  easily  be  computed. 


PLANT-FOOD  SUPPLY 

Of  the  elements  of  plant  food,  three  (carbon,  oxygen,  and  hydrogen)  are 
secured  from  air  and  water,  and  the  others  from  the  soil.  Nitrogen,  one  of  the 
elements  obtained  from  the  soil  by  all  plants,  may  also  be  secured  from  the  air 
by  the  class  of  plants  known  as  legumes,  in  case  the  amount  liberated  from  the 


Logan  County 


27 


Table  6. ^Plant-Food  Elements  in  Manure,  Rough  Feeds,  and  Fertilizers' 

Material 

Pounds  of  plant  food 
of  material 

per  ton 

Nitrogen 

Phosphorus 

Potassium 

Fresh  farm  manure 

10 

16 
12 
10 

40 
43 

50 
80 

280 
310 
400 

80 
20 

2 

2 
2 
2 

5 
5 
4 

8 

180 
250 
250 
125 

"io' 

8 

Corn  stover 

17 

Oat  straw 

21 

Wheat  straw 

18 

Clover  hay 

30 

Cowpea  hay 

33 

Alfalfa  hay 

24 

Sweet  clover  (water-free  basis)  ^ 

28 

Dried  blood 

Sodium  nitrate 

Ammonium  sulfate 

Raw  bone  meal 

Steamed  bone  meal 

Raw  rock  phosphate 

Acid  phosphate   

Potassium  chlorid   

850 

Potassium  sulfate 

850 

Kainit 

Wood  ashes^  (unleached) 

200 
100 

'See  footnote  to  Table  5. 

^Young  second-year  growth  ready  to  plow  under  as  green  manure. 

'Wood  ashes  also  contain  about  1,000  pounds  of  lime  (calcium  carbonate)  per  ton. 

soil  is  insufficient;  but  even  these  plants,  which  include  only  the  clovers,  peas, 
beans,  and  vetches  among  our  common  agricultural  plants,  are  dependent  upon 
the  soil  for  the  other  six  elements  (phosphorus,  potassium,  magnesium,  calcium, 
iron,  and  sulfur),  and  they  also  utilize  the  soil  nitrogen  so  far  as  it  becomes 
soluble  and  available  during  their  period  of  growth. 

The  vast  difference  with  respect  to  the  supply  of  these  essential  plant-food 
elements  in  different  soils  is  well  brought  out  in  the  data  of  the  Illinois  soil 
survey.  For  example,  it  has  been  found  that  the  nitrogen  in  the  surface  6% 
inches,  which  represents  the  plowed  stratum,  varies  in  amount  from  180  pounds 
per  acre  to  more  than  35,000  pounds.  In  like  manner  the  phosphorus  content 
varies  from  about  320  to  4,900  pounds,  and  the  potassium  ranges  from  1,530  to 
about  58,000  pounds.  Similar  variations  are  found  in  all  of  the  other  essential 
plant-food  elements  of  the  soil. 

With  these  facts  in  mind  it  is  easy  to  understand  how  a  deficiency  of  one 
of  these  elements  of  plant  food  may  become  a  limiting  factor  of  crop  production. 
When  an  element  becomes  so  reduced  in  quantity  as  to  become  a  limiting  factor 
of  production,  then  we  must  look  for  some  outside  source  of  supply.  Table  6 
is  presented  for  the  purpose  of  furnishing  information  regarding  the  quantity 
of  some  of  the  more  important  plant-food  elements  contained  in  materials  most 
commonly  used  as  sources  of  supply. 


28  Soil  Eeport  No.  39:    Appendix 

LIBERATION  OF  PLANT  FOOD 

The  chemical  analysis  of  the  soil  gives  the  invoice  of  plant-food  elements 
actually  present  in  the  soil  strata  sampled  and  analyzed,  but  the  rate  of  libera- 
tion is  governed  by  many  factors,  some  of  which  may  be  controlled  by  the  farmer, 
while  others  are  largely  beyond  his  control.  Chief  among  the  important  con- 
trollable factors  which  influence  the  liberation  of  plant  food  are  the  choice  of 
crops  to  be  grown,  the  use  of  limestone,  and  the  incorporation  of  organic  matter. 
Tillage,  especially  plowing,  also  has  a  considerable  effect  in  this  connection. 

Feeding  Power  of  Plants. — Different  species  of  plants  exhibit  a  very  great 
diversity  in  their  ability  to  obtain  plant  food  directly  from  the  insoluble  minerals 
of  the  soil.  As  a  class,  the  legumes — especially  such  biennial  and  perennial 
legumes  as  red  clover,  sweet  clover,  and  alfalfa — are  endowed  with  unusual 
power  to  assimilate  from  mineral  sources  such  elements  as  calcium  and  phos- 
phorus, converting  them  into  available  forms  for  the  crops  that  follow.  For  this 
reason  it  is  especially  advantageous  to  employ  such  legumes  in  connection  with 
the  application  of  limestone  and  rock  phosphate.  Thru  their  growth  and  subse- 
quent decay  large  quantities  of  the  mineral  elements  are  liberated  for  the  benefit 
of  the  cereal  crops  which  follow  in  the  rotation.  Moreover,  as  an  effect  of  the 
deep-rooting  habit  of  these  legumes,  mineral  plant-food  elements  are  brought  up 
and  rendered  available  from  the  vast  reservoirs  of  the  lower  subsoil. 

Effect  of  Limestone. — Limestone  corrects  the  acidity  of  the  soil  and  supplies 
calcium,  thus  encouraging  the  development  not  only  of  the  nitrogen-gathering 
bacteria  which  live  in  the  nodules  on  the  roots  of  clover,  cowpeas,  and  other 
legumes,  but  also  the  nitrifying  bacteria,  which  have  power  to  transform  the 
unavailable  organic  nitrogen  into  available  nitrate  nitrogen.  At  the  same  time, 
the  products  of  this  decomposition  have  power  to  dissolve  the  minerals  contained 
in  the  soil,  such  as  potassium  and  magnesium  compounds. 

Organic  Matter  and  Biological  Action. — Organic  matter  may  be  supplied 
thru  animal  manures,  consisting  of  the  excreta  of  animals  and  usually  accom- 
panied by  more  or  less  stable  litter;  and  by  plant  manures,  including  green- 
manure  crops  and  cover  crops  plowed  under,  and  also  crop  residues  such  as  stalks, 
straw,  and  chaff.  The  rate  of  decay  of  organic  matter  depends  largely  upon  its 
age,  condition,  and  origin,  and  it  may  be  hastened  by  tillage.  The  chemical 
analysis  shows  correctly  the  total  organic  carbon,  which  constitutes,  as  a  rule, 
but  little  more  than  half  the  organic  matter;  so  that  20,000  pounds  of  organic 
carbon  in  the  plowed  soil  of  an  acre  corresponds  to  nearly  20  tons  of  organic 
matter.  But  this  organic  matter  consists  largely  of  the  old  organic  residues  that 
have  accumulated  during  the  past  centuries  because  they  were  resistant  to  decay, 
and  2  tons  of  clover  or  cowpeas  plowed  under  may  have  greater  power  to  liberate 
plant-food  materials  than  20  tons  of  old,  inactive  organic  matter.  The  history  of 
the  individual  farm  or  field  must  be  depended  upon  for  information  concerning 
recent  additions  of  active  organic  matter,  whetlier  in  applications  of  farm  manure, 
in  legume  crops,  or  in  sods  of  old  pastures. 

The  condition  of  the  organic  matter  of  the  soil  is  indicated  to  some  extent 
by  the  ratio  of  carbon  to  nitrogen.  Fresh  organic  matter  recently  incorporated 
with  the  soil  contains  a  very  much  higher  proportion  of  carbon  to  nitrogen  than 


Logan  County  29 

do  the  old  resistant  organic  residues  of  the  soil.  The  proportion  of  carbon  to 
nitrogen  is  higher  in  the  surface  soil  than  in  the  corresponding  subsoil,  and  in 
general  this  ratio  is  wider  in  highly  productive  soils  well  charged  with  active 
organic  matter  than  in  very  old,  worn  soils  badly  in  need  of  active  organic  matter. 

The  organic  matter  furnishes  food  for  bacteria,  and  as  it  decays  certain 
decomposition  products  are  formed,  including  much  carbonic  acid,  some  nitrous 
acid,  and  various  organic  acids,  and  these  acting  upon  the  soil  have  the  power  to 
dissolve  the  essential  mineral  plant  foods,  thus  furnishing  available  phosphates, 
nitrates,  and  other  salts  of  potassium,  magnesium,  calcium,  etc.,  for  the  use  of 
the  growing  crop. 

Effect  of  Tillage. — Tillage,  or  cultivation,  also  hastens  the  liberation  of  plant- 
food  elements  by  permitting  the  air  to  enter  the  soil.  It  should  be  remembered, 
however,  that  tillage  is  wholly  destructive,  in  that  it  adds  nothing  whatever  to 
the  soil,  but  always  leaves  it  poorer,  so  far  as  plant-food  materials  are  concerned. 
Tillage  should  be  practiced  so  far  as  is  necessary  to  prepare  a  suitable  seed  bed 
for  root  development  and  also  for  the  purpose  of  killing  weeds,  but  more  than 
this  is  unnecessary  and  unprofitable;  and  it  is  much  better  actually  to  enrich 
the  soil  by  proper  applications  of  limestone,  organic  matter,  and  other  fertilizing 
materials,  and  thus  promote  soil  conditions  favorable  for  vigorous  plant  growth, 
than  to  depend  upon  excessive  cultivation  to  accomplish  the  same  object  at  the 
expense  of  the  soil. 

PERMANENT  SOIL  IMPROVEMENT 

According  to  the  kind  of  soil  involved,  any  comprehensive  plan  contemplat- 
ing a  permanent  system  of  agriculture  will  need  to  take  into  account  some  of  the 
following  considerations. 

The  Application  of  Limestone 

The  Function  of  Limestone. — In  considering  the  application  of  limestone 
to  land  it  should  be  understood  that  this  material  functions  in  several  different 
ways,  and  that  a  beneficial  result  may  therefore  be  attributable  to  quite  diverse 
causes.  Limestone  provides  calcium,  of  which  certain  crops  are  strong  feeders. 
It  corrects  acidity  of  the  soil,  thus  making  for  some  crops  a  much  more  favorable 
environment  as  well  as  establishing  conditions  absolutely  required  for  some  of 
the  beneficial  legume  bacteria.  It  accelerates  nitrification  and  nitrogen  fixation. 
It  promotes  sanitation  of  the  soil  by  inhibiting  the  growth  of  certain  fungous 
diseases,  such  as  corn-root  rot.  Experience  indicates  that  it  modifies  either 
directly  or  indirectly  the  physical  structure  of  fine-textured  soils,  frequently  to 
their  great  improvement.  Thus,  working  in  one  or  more  of  these  different  ways, 
limestone  often  becomes  the  key  to  the  improvement  of  worn  lands. 

Hoiv  to  Ascertain  the  Need  for  Limestone. — One  of  the  most  reliable  indica- 
tions as  to  whether  a  soil  needs  limestone  is  the  character  of  the  growth  of  certain 
legumes,  particularly  sweet  clover  and  alfalfa.  Tliese  crops  do  not  thrive  in 
acid  soils.  Their  successful  growth,  therefore,  indicates  the  lack  of  sufficient 
acidity  in  the  soil  to  be  harmful.    In  case  of  their  failure  to  grow  the  soil  should 


^0  Soil  Keport  No.  39:    Appendix 

be  tested  for  acidity  as  described  below.  A  very  valuable  test  for  ascertaining 
the  need  of  a  soil  for  limestone  is  found  in  the  potassium  thiocyanate  test  for  soil 
acidity.  It  is  desirable  to  make  the  test  for  carbonates  along  with  the  acidity 
test.  Limestone  is  calcium  carbonate,  while  dolomite  is  the  combined  carbonates 
of  calcium  and  magnesium.  The  natural  occurrence.of  these  carbonates  in  the 
soil  is  sufficient  assurance  that  no  limestone  is  needed,  and  the  acidity  test  will 
be  negative.  On  lands  which  have  been  treated  with  limestone,  however,  the 
surface  soil  may  give  a  positive  test  for  carbonates,  owing  to  the  presence  of 
undecomposed  pieces  of  limestone,  and  at  the  same  time  a  positive  test  for  acidity 
may  be  secured.  Such  a  result  means  either  that  insufficient  limestone  has  been 
added  to  neutralize  the  acidity,  or  that  it  has  not  been  in  the  soil  long  enough 
to  entirely  correct  the  acidity.  In  making  these  tests,  it  is  desirable  to  examine 
samples  of  soil  from  different  depths,  since  carbonates  may  be  present,  even  in 
abundance,  below  a  surface  stratum  that  is  acid.  Following  are  the  directions 
for  making  the  tests : 

The  Potassium  Thiocyanate  Test  for  Acidity.    This  test  is  made  with  a  4-percent  solu- 
lon  of  potassium  thiocyanate  in  alcohol-4  grams  of  potassium  thiocyanate  in  WO  cuMc 

witlTh'f 'l  r^^"P''''°'  ^^!,'^°1-'  ^""^^^  ^  «°^^"  "^^^^'^'y  «f  ««il  shaken  up  in  a  test  tube 
w  th  this  solution  gives  a  red  color  the  soil  is  acid  and  limestone  should  be  applied.    If  the 

Uon  Tr.T"T'"^'"V\'fV'  r  "^^^-  ^"  ^^^^^^  «^  ^^ter  interferes  with  the  reac- 
^ood  tmabl?3nH-r  l"''^'  t^^--^^^^^'  «J^«"ld  be  at  least  as  dry  as  when  the  soil  is  in 

fhould  b.  nn.Tn  ?^  ^,^\^  F''''^'^}  '"'^^^^^  ^^^  temperature  of  the  soil  and  solution 
should  be  not  lower  than  that  of  comfortable  working  conditions  (60"  to  75°  Fahrenheit) 

soil  Jn^<f  .^^^''"'^^'"f'  Acid  Test  for  Carbonates.  Take  a  small  representative  sample  of 
soil  and  pour  upon  it  a  few  drops  of  hydrochloric  (muriatic)  acid,  prepared  by  diluting  the 

arbonat'e  t-?r^   ^l'""  ""VZ^'  "°'"'"^  ''  ""^^^-     '^^^  P^^«^°««  of  liiSestone  "[.r  some  ?ther 
carbonates  will  be  shown  by  the  appearance  of  gas  bubbles  within  2  or  3  minutes,  producing 

fw  '  f  •°''  ^ff^^esce^ce-.  The  absence  of  carbonates  in  a  soil  is  not  in  itself  evidence  that 
tne  soil  IS  acid  or  that  limestone  should  be  applied,  but  it  indicates  that  the  confirmatory 
potassium  thiocyanate  test  should  be  carried  out. 

Amounts  to  Apply.— Acid  soils  should  be  treated  with  limestone  whenever 
such  application  is  at  all  practicable.  The  initial  application  varies  with  the 
degree  of  acidity  and  will  usually  range  from  2  to  6  tons  an  acre.  The  larger 
amounts  will  be  needed  on  strongly  acid  soils,  particularly  on  land  being  pre- 
pared for  alfalfa.  When  sufficient  limestone  has  been  used  to  establish  condi- 
tions favorable  to  the  growth  of  legumes,  no  further  applications  are  necessary 
until  the  acidity  again  develops  to  such  an  extent  as  to  interfere  with  the  best 
growth  of  these  crops.  This  will  ordinarily  be  at  intervals  of  several  years.  In 
the  ease  of  an  inadequate  supply  of  magnesium  in  the  soil,  the  occasional  use  of 
magnesian  (dolomitic)  limestone  would  serve  to  correct  this  deficiency.  Other- 
wise, so  far  as  present  knowledge  indicates,  either  form  of  limestone— high- 
calcium  or  magnesian— will  be  equally  efeective,  depending  upon  the  purity  and 
fineness  of  the  respective  stones. 

Fineness  of  Material— The  fineness  to  which  limestone  is  ground  is  an  im- 
portant consideration  in  its  use  for  soil  improvement.  Experiments  indicate  that 
a  considerable  range  in  this  regard  is  permissible.     Very  fine  grinding  insures 

f^^Jr-^^iT^  undenatured  alcohol  is  difficult  to  obtain,  some  of  the  denatured  alcohols  have  been 
tested  for  making  this  solution.  Completely  denatured  alcohol  made  over  U.  S.  Formulas  No 
1  and  No.  4,  have  been  found  satisfactory.  Some  commercial  firms  are  also  offering  other 
preparations  which  are  satisfactory.  s  "    ^ 


Logan  County  31 

ready  solubility,  and  thus  promptness  in  action;  but  the  finer  the  grinding  the 
greater  is  the  expense  involved.  A  grinding,  therefore,  that  furnishes  not  too 
large  a  proportion  of  coarser  particles  along  with  the  finer,  similar  to  that  of  the 
by-product  material  on  the  market,  is  to  be  recommended.  Altho  the  exact  pro- 
portions of  coarse  and  fine  material  cannot  be  prescribed,  it  may  be  said  that  a 
limestone  crushed  so  that  the  coarsest  fragments  will  pass  thru  a  screen  of  4  to  10 
meshes  to  the  inch  is  satisfactory  if  the  total  product  is  used. 

The  Nitrogen  Problem 

Nitrogen  presents  the  greatest  practical  soil  problem  in  American  agricul- 
ture. Four  important  reasons  for  this  are:  its  increasing  deficiency  in  most 
soils;  its  cost  when  purchased  on  the  open  market;  its  removal  in  large  amounts 
by  crops ;  and  its  loss  from  soils  thru  leaching.  Nitrogen  usually  costs  from  four 
to  five  times  as  much  per  pound  as  phosphorus.  A  100-bushel  crop  of  corn  re- 
quires 150  pounds  of  nitrogen  for  its  growth,  but  only  23  pounds  of  phosphorus. 
The  loss  of  nitrogen  from  soils  may  vary  from  a  few  pounds  to  over  one  hundred 
pounds  per  acre,  depending  upon  the  treatment  of  the  soil,  the  distribution  of 
rainfall,  and  the  protection  afforded  by  growing  crops. 

An  inexhaustible  supply  of  nitrogen  is  present  in  the  air.  Above  each  acre 
of  the  earth's  surface  there  are  about  sixty-nine  million  pounds  of  atmospheric 
nitrogen.  The  nitrogen  above  one  square  mile  weighs  twenty  million  tons,  an 
amount  sufficient  to  supply  the  entire  world  for  four  or  five  decades.  This  large 
supply  of  nitrogen  in  the  air  is  the  one  to  which  the  world  must  eventually  turn. 

There  are  two  methods  of  collecting  the  inert  nitrogen  gas  of  the  air  and 
combining  it  into  compounds  that  will  furnish  products  for  plant  growth.  These 
are  the  chemical  and  the  biological  fixation  of  the  atmospheric  nitrogen.  Farmers 
have  at  their  command  one  of  these  methods.  By  growing  inoculated  legumes, 
nitrogen  may  be  obtained  from  the  air,  and  by  plowing  under  more  than  the  roots 
of  these  legumes,  nitrogen  may  be  added  to  the  soil. 

Inasmuch  as  legumes  are  worth  growing  for  purposes  other  than  the  fixation 
of  atmospheric  nitrogen,  a  considerable  portion  of  the  nitrogen  thus  gained  may 
be  considered  a  by-product.  Because  of  that  fact,  it  is  questionable  whether  the 
chemical  fixation  of  nitrogen  will  ever  be  able  to  replace  the  simple  method  of 
obtaining  atmospheric  nitrogen  by  growing  inoculated  legumes  in  the  production 
of  our  great  grain  and  forage  crops. 

It  may  well  be  kept  in  mind  that  the  following  amounts  of  nitrogen  are  re- 
quired for  the  produce  named : 

1  bushel  of  oats  (grain  and  straw)  requires  1  pound  of  nitrogen. 

1  bushel  of  com  (grain  and  stalks)  requires  1^  pounds  of  nitrogen. 

1  bushel  of  wheat  (grain  and  straw)  requires  2  pounds  of  nitrogen. 

1  ton  of  timothy  contains  24  pounds  of  nitrogen. 

1  ton  of  clover  contains  40  pounds  of  nitrogen. 

1  ton  of  cowpea  hay  contains  43  pounds  of  nitrogen. 

1  ton  of  alfalfa  contains  50  pounds  of  nitrogen. 

1  ton  of  average  manure  contains  10  pounds  of  nitrogen. 

1  ton  of  young  sweet  clover,  at  about  the  stage  of  growth  when  it  is  plowed  under  as 
green  manure,  contains,  on  water-free  basis,  80  pounds  of  nitrogen. 

The  roots  of  clover  contain  about  half  as  much  nitrogen  as  the  tops,  and  the 
roots  of  cowpeas  contain  about  one-tenth  as  much  as  the  tops.     Soils  of  mod- 


32  Soil  Report  No.  39:    Appendix 

erate  productive  power  will  furnish  as  much  nitrogen  to  clover  (and  two  or  three 
times  as  much  to  cowpeas)  as  will  be  left  in  the  roots  and  stubble.  In  grain 
crops,  such  as  wheat,  corn,  and  oats,  about  two-thirds  of  the  nitrogen  is  con- 
tamed  in  the  grain  and  one-third  in  the  straw  or  stalks. 

The  Phosphorus  Problem 
The  element  phosphorus  is  an  indispensable  constituent  of  every  living  cell. 
It  IS  intimately  connected  with  the  life  processes  of  both  plants  and  animals,  the 
nuclear  material  of  the  cells  being  especially  rich  in  this  element. 

The  phosphorus  content  of  the  soil  is  dependent  upon  the  origin  of  the  soil. 
The  removal  of  phosphorus  by  continuous  cropping  slowly  reduces  the  amount 
of  this  element  m  the  soil  available  for  crop  use,  unless  its  addition  is  provided 
for  by  natural  means,  such  as  overflow,  or  by  agricultural  practices,  such  as  the 
addition  of  phosphatic  fertilizers  and  rotations  in  which  deep-rooting,  leguminous 
crops  are  frequently  grown. 

It  should  be  borne  in  mind  in  connection  with  the  application  of  phosphate 
or  of  any  other  fertilizing  material,  to  the  soil,  that  no  benefit  can  result  until 
the  need  for  it  has  become  a  limiting  factor  in  plant  growth.  For  example  if 
there  is  already  present  in  the  soil  sufficient  available  phosphorus  to  produce  a 
forty-bushel  crop,  and  the  nitrogen  supply  or  the  moisture  supply  is  sufficient 
for  only  forty  bushels,  or  less,  then  extra  phosphorus  added  to  the  soil  cannot 
increase  the  yield  beyond  this  forty-bushel  limit. 

There  are  several  different  materials  containing  phosphorus  which  are 
applied  to  land  as  fertilizer.  The  more  important  of  these  are  bone  meal,  acid 
phosphate,  natural  raw  rock  phosphate,  and  basic  slag.  Obviously  that  carrier 
of  phosphorus  which  gives  the  most  economical  returns,  as  considered  from  all 
standpomts,  is  the  most  suitable  one  to  use.  Altho  this  matter  has  been  the 
subject  of  much  discussion  and  investigation  the  question  still  remains  unsettled 
Probably  there  is  no  single  carrier  of  phosphorus  that  will  prove  to  be  the  most 
economical  one  to  use  under  all  circumstances  because  so  much  depends  upon 
soil  conditions,  crops  grown,  length  of  haul,  and  market  conditions. 

Bone  meal,  prepared  from  the  bones  of  animals,  appears  on  the  market  in 
two  different  forms,  raw  and  steamed.  Raw  bone  meal  contains,  besides  the 
phosphorus,  a  considerable  percentage  of  nitrogen  which  adds  a  useless  expense 
If  the  material  is  purchased  only  for  the  sake  of  the  phosphorus.  As  a  source  of 
phosphorus,  steamed  bone  meal  is  preferable  to  raw  bone  meal.  Steamed  bone 
meal  is  prepared  by  extracting  most  of  the  nitrogeneous  and  fatty  matter  from 
the  bones,  thus  producing  a  more  nearly  pure  form  of  calcium  phosphate  con- 
taining about  10  to  12  percent  of  the  element  phosphorus. 

Acid  phosphate  is  produced  by  treating  rock  phosphate  with  sulfuric  acid 
The  two  are  mixed  in  about  equal  amounts ;  the  product  therefore  contains  about 
one-half  as  much  phosphorus  as  the  rock  phosphate  itself.  Besides  phosphorus 
acid  phosphate  also  contains  sulfur,  which  is  likewise  an  element  of  plant  food' 
The  phosphorus  in  acid  phosphate  is  more  readily  available  for  absorption  by 
plants  than  that  of  raw  rock  phosphate.  Acid  phosphate  of  good  quality  should 
contain  6  percent  or  more  of  the  element  phosphorus. 


Logan  County  33 

Rock  phosphate,  sometimes  called  floats,  is  a  mineral  substance  found  in 
vast  deposits  in  certain  regions.  The  phosphorus  in  this  mineral  exists  chemically 
as  tri-calcium  phosphate,  and  a  good  grade  of  the  rock  should  contain  121/2 
percent,  or  more,  of  the  element  phosphorus.  The  rock  should  be  ground  to  a 
powder,  fine  enough  to  pass  thru  a  100-mesh  sieve,  or  even  finer. 

The  relative  cheapness  of  raw  rock  phosphate,  as  compared  with  the  treated 
or  acidulated  material,  makes  it  possible  to  apply  for  equal  money  expenditure 
considerably  more  phosphorus  per  acre  in  this  form  than  in  the  form  of  acid 
phosphate,  the  ratio  being,  under  the  market  conditions  of  the  past  several  years, 
about  4  to  1.  That  is  to  say,  under  these  market  conditions,  a  dollar  will  pur- 
chase about  four  times  as  much  of  the  element  phosphorus  in  the  form  of  rock 
phosphate  as  in  the  form  of  acid  phosphate,  which  is  an  important  consideration 
if  one  is  interested  in  building  up  a  phosphorus  reserve  in  the  soil.  As  explained 
above,  more  very  carefully  conducted  comparisons  on  various  soil  types  under 
various  cropping  systems  are  needed  before  definite  statements  can  be  given  as 
to  which  form  of  phosphate  is  most  economical  to  use  under  any  given  set  of 
conditions. 

Basic  slag,  known  also  as  Thomas  phosphate,  is  another  carrier  of  phos- 
phorus that  might  be  mentioned  because  of  its  considerable  usage  in  Europe 
and  eastern  United  States.  Basic  slag  phosphate  is  a  by-product  in  the  manu- 
facture of  steel.  It  contains  a  considerable  proportion  of  basic  material  and 
therefore  it  tends  to  influence  the  soil  reaction. 

Rock  phosphate  may  be  applied  at  any  time  during  a  rotation,  but  it  is 
applied  to  the  best  advantage  either  preceding  a  crop  of  clover,  which  plant 
seems  to  possess  an  unusual  power  for  assimilating  the  phosphorus  from  raw 
phosphate,  or  else  at  a  time  when  it  can  be  plowed  under  with  some  form  of 
organic  matter  such  as  animal  manure  or  green  manure,  the  decay  of  which 
serves  to  liberate  the  phosphorus  from  its  insoluble  condition  in  the  rock.  It  is 
important  that  the  finely  ground  rock  phosphate  be  intimately  mixed  with  the 
organic  material  as  it  is  plowed  under. 

In  using  acid  phosphate  or  bone  meal  in  a  cropping  system  which  includes 
wheat,  it  is  a  common  practice  to  apply  the  material  in  the  preparation  of  the 
wheat  ground.  It  may  be  advantageous,  however,  to  divide  the  total  amount 
to  be  used  and  apply  a  portion  to  the  other  crops  of  the  rotation,  particularly 
to  corn  and  to  clover. 

The  Potassium  Problem 

Our  most  common  soils,  which  are  silt  loams  and  clay  loams,  are  well  stocked 
with  potassium,  altho  it  exists  largely  in  a  slowly  soluble  form.  Such  soils  as 
sands  and  peats,  however,  are  likely  to  be  low  in  this  element.  On  such  soils  this 
deficiency  may  be  remedied  by  the  application  of  some  potassium  salt,  such  as 
potassium  sulfate,  potassium  chlorid,  kainit,  or  other  potassium  compound,  and  in 
many  instances  this  is  done  at  great  profit. 

From  all  the  facts  at  hand  it  seems,  so  far  as  our  great  areas  of  common 
soils  are  concerned,  that,  with  a  few  exceptions,  the  potassium  problem  is  not 
one  of  addition  but  of  liberation.    The  Rothamsted  records,  which  represent  the 


34  Soil  Report  No.  39:    Appendix 

oldest  soil  experiment  fields  in  the  world,  show  that  for  many  years  other  soluble 
salts  have  had  practically  the  same  power  as  potassium  salts  to  increase  crop 
yields  in  the  absence  of  sufficient  decaying  organic  matter.  Whether  this  action 
relates  to  supplying  or  liberating  potassium  for  its  own  sake,  or  to  the  power 
of  the  soluble  salt  to  increase  the  availability  of  phosphorus  or  other  elements, 
is  not  known,  but  where  much  potassium  is  removed,  as  in  the  entire  crops  at 
Rothamsted,  with  no  return  of  organic  residues,  probably  the  soluble  salt  func- 
tions in  both  ways. 

Further  evidence  on  this  matter  is  furnished  by  the  Illinois  experiment  field 
at  Fairfield,  where  potassium  sulfate  has  been  compared  with  kainit  both  with 
and  without  the  addition  of  organic  matter  in  the  form  of  stable  manure.  Both 
sulfate  and  kainit  produced  a  substantial  increase  in  the  yield  of  corn,  but  the 
cheaper  salt — kainit — was  just  as  effective  as  the  potassium  sulfate,  and  returned 
some  financial  profit.  Manure  alone  gave  an  increase  similar  to  that  produced 
by  the  potassium  salts,  but  the  salts  added  to  the  manure  gave  very  little  increase 
over  that  produced  by  the  manure  alone.  This  is  explained  in  part,  perhaps,  by 
the  fact  that  the  potassium  removed  in  the  crops  is  mostly  returned  in  manure 
properly  cared  for,  and  perhaps  in  larger  part  by  the  fact  that  decaying  organic 
matter  helps  to  liberate  and  hold  in  solution  other  plant-food  elements,  especially 
phosphorus. 

In  laboratory  experiments  at  the  Illinois  Experiment  Station,  it  has  been 
shown  that  potassium  salts  and  most  other  soluble  salts  increase  the  solubility  of 
the  phosphorus  in  soil  and  in  rock  phosphate;  also  that  the  addition  of  glucose 
with  rock  phosphate  in  pot-culture  experiments  increases  the  availability  of  the 
phosphorus,  as  measured  by  plant  growth,  altho  the  glucose  consists  only  of  car- 
bon, hydrogen,  and  oxygen,  and  thus  contains  no  limiting  element  of  plant  food. 

In  considering  the  conservation  of  potassium  on  the  farm  it  should  be  re- 
membered that  in  average  livestock  farming  the  animals  destroy  two-thirds  of 
the  organic  matter  and  retain  one-fourth  of  the  nitrogen  and  phosphorus  from 
the  food  they  consume,  but  that  they  retain  less  than  one-tenth  of  the  potassium ; 
so  that  the  actual  loss  of  potassium  in  the  products  sold  from  the  farm,  either 
in  grain  farming  or  in  livestock  farming,  is  negligible  on  land  containing  25,000 
pounds  or  more  of  potassium  in  the  surface  6%  inches. 

The  Calcium  and  Magnesium  Problem 

When  measured  by  crop  removals  of  the  plant-food  elements,  calcium  is 
often  more  limited  in  Illinois  soils  than  is  potassium,  while  magnesium  may  be 
occasionally.  In  the  case  of  calcium,  however,  the  deficiency  is  likely  to  develop 
more  rapidly  and  become  much  more  marked  because  this  element  is  leached 
out  of  the  soil  in  drainage  water  to  a  far  greater  extent  than  is  either  magnesium 
or  potassium. 

The  annual  loss  of  limestone  from  the  soil  depends,  of  course,  upon  a  num- 
ber of  factors  aside  from  those  which  have  to  do  with  climatic  conditions.  Among 
these  factors  may  be  mentioned  the  character  of  the  soil,  the  kind  of  limestone, 
its  condition  of  fineness,  the  amount  present,  and  the  sort  of  farming  practiced. 
Because  of  this  variation  in  the  loss  of  lime  materials  from  the  soil,  it  is  impossible 


Logan  County  35 

to  prescribe  a  fixed  practice  in  their  renewal  that  will  apply  universally.  The 
tests  for  acidity  and  carbonates  described  above,  together  with  the  behavior  of 
such  linie-loving  legumes  as  alfalfa  and  sweet  clover,  will  serve  as  general 
indicators  for  the  frequeilcy  of  applying  limestone  and  the  amount  to  use  on  a 
given  field. 

Limestone  has  a  direct  value  on  some  soils  for  the  plant  food  which  it 
supplies,  in  addition  to  its  value  in  correcting  soil  acidity  and  in  improving  the 
physical  condition  of  the  soil.  Ordinary  limestone  (abundant  in  the  southern 
and  western  parts  of  Illinois)  contains  nearly  800  pounds  of  calcium  per  ton; 
while  a  good  grade  of  dolomitic  limestone  (the  more  common  limestone  of  north- 
ern Illinois)  contains  about  400  pounds  of  calcium  and  300  pounds  of  magnesium 
per  ton.  Both  of  these  elements  are  furnished  in  readily  available  form  in 
ground  dolomitic  limestone. 

The  Sulfur  Question 

In  considering  the  relation  of  sulfur  in  a  permanent  system  of  soil  fertility 
it  is  important  to  understand  something  of  the  cycle  of  transformations  that  this 
element  undergoes  in  nature.    Briefly  stated  this  is  as  follows : 

Sulfur  exists  in  the  soil  in  both  organic  and  inorganic  forms,  the  former 
being  gradually  converted  to  the  latter  form  thru  bacterial  action.  In  this 
inorganic  form  sulfur  is  taken  up  by  plants  which  in  their  physiological  processes 
change  it  once  more  into  an  organic  form  as  a  constituent  of  protein.  When 
these  plant  proteins  are  consumed  by  animals,  the  sulfur  becomes  a  part  of  the 
animal  protein.  When  these  plant  and  animal  proteins  are  decomposed,  either 
thru  bacterial  action,  or  thru  combustion,  as  in  the  burning  of  coal,  the  sulfur 
passes  into  the  atmosphere  or  into  the  soil  solution  in  the  form  of  sulfur  dioxid 
gas.  This  gas  unites  with  oxygen  and  water  to  form  sulfuric  acid,  which  is 
readily  washed  back  into  the  soil  by  the  rain,  thus  completing  the  cycle,  from 
soil — to  plants  and  animals — to  air — to  soil. 

In  this  way  sulfur  becomes  largely  a  self -renewing  element  of  the  soil,  altho 
there  is  a  considerable  loss  from  the  soil  by  leaching.  Observations  taken  at  the 
Illinois  Agricultural  Experiment  Station  show  that  40  pounds  of  sulfur  per  acre 
are  brought  into  the  soil  thru  the  annual  rainfall.  With  a  fair  stock  of  sulfur, 
such  as  exists  in  our  common  types  of  soil,  and  with  an  annual  return,  which  of 
itself  would  more  than  suffice  for  the  needs  of  maximum  crops,  the  maintenance 
of  an  adequate  sulfur  supply  presents  little  reason  at  present  for  serious  concern. 
There  are  regions,  however,  where  the  natural  stock  of  sulfur  in  the  soil  is  not 
nearly  so  high  and  where  the  amount  returned  thru  rainfall  is  small.  Under  such 
circumstances  sulfur  soon  becomes  a  limiting  element  of  crop  production,  and  it 
will  be  necessary  sooner  or  later  to  introduce  this  substance  from  some  outside 
source.  Investigation  is  now  under  way  to  determine  to  what  extent  this  situation 
may  apply  under  Illinois  conditions. 

Physical  Improvement  of  Soils 

In  the  management  of  most  soil  types,  one  very  important  matter,  aside  from 
proper  fertilization,  tillage,  and  drainage,  is  to  keep  the  soil  in  good  physical 


36  Soil  Report  No.  39:    Appendix 

condition,  or  good  tilth.  The  constituent  most  important  for  this  purpose  is 
organic  matter.  Organic  matter  in  producing  good  tilth  helps  to  control  washing 
of  soil  on  rolling  land,  raises  the  temperature  of  drained  soil,  increases  the 
moisture-holding  capacity  of  the  soil,  slightly  retards  capillary  rise  and  conse- 
quently loss  of  moisture  by  surface  evaporation,  and  helps  to  overcome  the 
tendency  of  some  soils  to  run  together  badly. 

Tiie  physical  effect  of  organic  matter  is  to  produce  a  granulation  or  mellow- 
ness, by  cementing  the  fine  soil  particles  into  crumbs  or  grains  about  as  large  as 
grains  of  sand,  which  produces  a  condition  very  favorable  for  tillage,  percolation 
of  rainfall,  and  ihe  development  of  plant  roots. 

Organic  matter  is  undergoing  destruction  during  a  large  part  of  the  year 
and  the  nitrates  produced  in  its  decomposition  are  used  for  plant  growth.  Altho 
this  decomposition  is  necessary,  it  nevertheless  reduces  the  amount  of  organic 
matter,  and  provision  must  therefore  be  made  for  maintaining  the  supply.  The 
practical  way  to  do  this  is  to  turn  under  the  farm  manure,  straw,  cornstalks, 
weeds,  and  all  or  part  of  the  legumes  produced  on  the  farm.  The  amount  of 
legumes  needed  depends  upon  the  character  of  the  soil.  There  are  farms,  espe- 
cially grain  farms,  in  nearly  every  community  where  all  legumes  could  be  turned 
under  for  several  years  to  good  advantage. 

Manure  should  be  spread  upon  the  land  as  soon  as  possible  after  it  is  pro- 
duced, for  if  it  is  allowed  to  lie  in  the  barnyard  several  months  as  is  so  often  the 
case,  from  one-third  to  two-thirds  of  the  organic  matter  will  be  lost. 

Straw  and  cornstalks  should  be  turned  under,  and  not  burned.  There  is 
considerable  evidence  indicating  that  on  some  soils  undecomposed  straw  applied 
in  excessive  amount  may  be  detrimental.  Probably  the  best  practice  is  to  apply 
the  straw  as  a  constituent  of  well-rotted  stable  manure.  Perhaps  no  form  of 
organic  matter  acts  more  beneficially  in  producing  good  tilth  than  cornstalks.  It 
is  true,  they  decay  rather  slowly,  but  it  is  also  true  that  their  durability  in  the 
soil  is  exactly  what  is  needed  in  the  production  of  good  tilth.  Furthermore,  the 
nitrogen  in  a  ton  of  cornstalks  is  one  and  one-half  times  that  of  a  ton  of  manure, 
and  a  ton  of  dry  cornstalks  incorporated  in  the  soil  will  ultimately  furnish  as 
much  humus  as  four  tons  of  average  farm  manure.  When  burned,  however,  both 
the  humus-making  material  and  the  nitrogen  are  lost  to  the  soil. 

It  is  a  common  practice  in  the  corn  belt  to  pasture  the  cornstalks  during 
the  winter  and  often  rather  late  in  the  spring  after  the  frost  is  out  of  the  ground. 
This  trampling  by  stock  sometimes  puts  the  soil  in  bad  condition  for  working. 
It  becomes  partially  puddled  and  will  be  cloddy  as  a  result.  If  tramped  too  late 
in  the  spring,  the  natural  agencies  of  freezing  and  thawing  and  wetting  and 
drying,  with  the  aid  of  ordinary  tillage,  fail  to  produce  good  tilth  before  the 
crop  is  planted.  Whether  the  crop  be  corn  or  oats,  it  necessarily  suffers  and  if 
the  season  is  dry,  much  damage  may  be  done.  If  the  field  is  put  in  corn,  a  poor 
stand  is  likely  to  result,  and  if  put  in  oats,  the  soil  is  so  compact  as  to  be  un- 
favorable for  their  growth.  Sometimes  the  soil  is  worked  when  too  wet.  This 
also  produces  a  partial  puddling  which  is  unfavorable  to  physical,  chemical,  and 
biological  processes.  The  effect  becomes  worse  if  cropping  has  reduced  the  organic 
matter  below  the  amount  necessary  to  maintain  good  tilth. 


Logan  County  S7 

Systems  of  Crop  Rotations 

In  a  program  of  permanent  soil  improvement  one  should  adopt  at  the  outset 
a  good  rotation  of  crops,  including,  for  the  reasons  discussed  above,  a  liberal 
use  of  legumes.  No  one  can  say  in  advance  for  every  particular  case  what  will 
prove  to  be  the  best  rotation  of  crops,  because  of  variation  in  farms  and  farmers 
and  in  prices  for  produce.  As  a  general  principle  the  shorter  rotations,  with 
the  frequent  introduction  of  leguminous  crops,  are  the  better  adapted  for  building 
up  poor  soils. 

Following  are  a  few  suggested  rotations  which  may  serve  as  models  or  out- 
lines to  be  modified  according  to  special  circumstances. 

Six- Year  Rotations 

First  year    — Corn 

Second  year — Corn 

Third  year  — Wheat  or  oats  (with  clover,  or  clover  and  grass) 

Fourth  year — Clover,  or  clover  and  grass 

Fifth  year  — Wheat  (with  clover),  or  grass  and  clover 

Sixth  year   — Clover,  or  clover  and  grass 

In  grain  farming,  with  small  grain  grown  the  third  and  fifth  years,  most 
of  the  unsalable  products  should  be  returned  to  the  soil,  and  the  clover  may  be 
clipped  and  left  on  the  land  or  returned  after  threshing  out  the  seed ;  or.  in 
livestock  farming,  the  field  may  be  used  three  years  for  timothy  and  clover 
pasture  and  meadow  if  desired.  The  system  may  be  reduced  to  a  five-year  rota- 
tion by  cutting  out  either  the  second  or  the  sixth  year,  and  to  a  four-year  system 
by  omitting  the  fifth  and  sixth  years,  as  indicated  below. 

The  two  following  rotations  are  suggested  as  especially  adapted  for  com- 
bating the  corn  borer : 

First  year      — Corn  First  year      — Corn 

Second  year  — Soybeans  Second  year  — Soybeans 

Third  year     —Small  grain   (with  legume)  Third  year     — Small  grain  (with  legume) 

Fourth  year  — Legume  Fourth  year  — Legume 

Fifth  year      — Corn  (for  silage)  Fifth  year      —Wheat   (with  alfalfa) 

Sixth  year      — Wheat  (with  sweet  clover)  Sixth  year      — Alfalfa 

Five-Year  Rotations 
First  year    — Corn 

Second  year — Wheat  or  oats  (with  clover,  or  clover  and  grass) 
Third  year  — Clover,  or  clover  and  grass 
Fourth  year — Wheat  (with  clover),  or  clover  and  grass 
Fifth  year   — Clover,  or  clover  and  grass 

First  year     — Corn 


r  vrsi  year     ■ — uorn 
Second  year — Soybeans 
Third  year  — Corn 
Fourth  year — Wheat   (with  legume) 
■Fifth  year  — Legume 

First  year    — Corn 

Second  year — Cowpeas  or  soybeans 

Third  year   — Wheat  (with  clover) 

Fourth  year — Clover 

Fifth  year   — Wheat  (with  clover) 


38 


Soil  Report  No.  39:    Appendix 


The  last  rotation  mentioned  above  allows  legumes  to  be  grown  four  times. 
Alfalfa  may  be  grown  on  a  sixth  field  rotating  over  all  fields  if  moved  every 
six  years. 


Tour- Year  Rotations 


First  year      — Corn 

Second  year  — Wheat  or  oats  (with  clover) 

Third  year     — Clover 

Fourth  year  — Wheat  (with  clover) 

-Coin 


First  year      — Coin 

Second  year  — Cowpeas  or  soybeans 

Third  year     — Wheat  (with  clover) 


Third  year 
Fo^irth  year 


First  year      ■ — Corn 

Second  year  — Corn 

Third  year     — Wheat  or  oats  (?vith  clover) 

Fourth  year  — Clover 

First  year      — Wheat  (with  clover) 

Second  year  — Clover 

Third  year     — Corn 

Fourth  year  — Oats  (with  clover) 


Alfalfa  may  be  grown  on  a  fifth  field  for  four  or  eight  years,  which  is  to  be 
alternated  with  one  of  the  four;  or  the  alfalfa  may  be  moved  every  five  years, 
and  thus  rotated  over  all  five  fields  every  twenty-five  years. 


Three-Year  Rotations 

First  year      — Corn  First  year 

Second  year  — Oats  or  wheat  (with  clover)  Second  year 

Third  year     — Clover  Third  year 


-Wheat  or  oats  (with  clover) 

-Corn 

-Cowpeas  or  soybeans 


By  allowing  the  clover,  in  the  last  rotation  mentioned,  to  grow  in  the  spring 
before  preparing  the  land  for  corn,  we  have  provided  a  system  in  which  legumes 
grow  on  every  acre  every  year.  This  is  likewise  true  of  the  following  suggested 
two-year  system: 

Two-Year  Rotations 

First  year      — Oats  or  wheat  (with  sweet  clover) 
Second  year  — Corn 

Altho  in  this  two-year  rotation  either  oats  or  wheat  is  suggested,  as  a  matter 
of  fact,  by  dividing  the  land  devoted  to  small  grain,  both  of  these  crops  can  be 
grown  simultaneously,  thus  providing  a  three-crop  system  in  a  two-year  cycle. 

It  should  be  understood  that  in  all  of  the  above  suggested  cropping  systems 
it  may  be  desirable  in  some  cases  to  substitute  barley  or  rye  for  the  wheat  or 
oats.  Or,  in  some  cases,  it  may  become  desirable  to  divide  the  acreage  of  small 
grain  and  grow  in  the  same  year  more  than  one  kind.  In  all  of  these  proposed 
rotations  the  word  clover  is  used  in  a  general  sense  to  designate  either  red  clover, 
alsike  clover,  or  sweet  clover,  or  it  may  include  alfalfa  used  as  a  biennial.  The 
mixing  of  alfalfa  with  clover  seed  for  a  legume  crop  is  a  recommendable  prac- 
tice. The  value  of  sweet  clover,  especially  as  a  green  manure  for  building  up 
depleted  soils,  as  well  as  a  pasture  and  hay-crop,  is  becoming  thoroly  established, 
and  its  importance  in  a  crop-rotation  program  may  well  be  emphasized. 


SUPPLEMENT:   EXPERIMENT  FIELD  DATA 

(Results  from  Experiment  Fields  on  Soil  Types  Similar  to  those  Occurring  in 

Logan  County) 

The  University  of  Illinois  has  operated  altogether  about  fifty  soil  experi- 
ment fields  in  different  sections  of  the  state  and  on  various  types  of  soil.  Altho 
some  of  these  fields  have  been  discontinued,  the  large  majority  are  still  in 
operation.  It  is  the  present  purpose  to  report  the  results  from  certain  of  these 
fields  located  on  types  of  soil  described  in  the  accompanying  soil  report. 

A  few  general  explanations  at  this  point,  which  apply  to  all  the  fields,  will 
relieve  the  necessity  of  numerous  repetitions  in  the  following  pages. 

Size  and  Arrangement  of  Fields 

The  soil  experiment  fields  vary  in  size  from  less  than  two  acres  up  to  40 
acres  or  more.  They  are  laid  off  into  series  of  plots,  the  plots  commonly  being 
either  one-fifth  or  one-tenth  acre  in  area.  Each  series  is  occupied  by  one  kind 
of  crop.  Usually  there  are  several  series  so  that  a  crop  rotation  can  be  carried  on 
with  every  crop  represented  every  year. 

Farming  Systems 

On  many  of  the  fields  the  treatment  provides  for  two  distinct  systems  of 
farming,  livestock  farming  and  grain  farming. 

In  the  livestock  system  stable  manure  is  used  to  furnish  organic  matter 
and  nitrogen.  The  amount  applied  to  a  plot  is  based  upon  the  amount  that  can 
be  produced  from  crops  raised  on  that  plot. 

In  the  grain  system  no  animal  manure  is  used.  The  organic  matter  and 
nitrogen  are  applied  in  the  form  of  plant  manures,  including  the  plant  residues 
produced,  such  as  cornstalks,  straw  from  wheat,  oats,  clover,  etc.,  along  with 
leguminous  catch  crops  plowed  under.  It  was  the  plan  in  this  latter  system  to 
remove  from  the  land,  in  the  main,  only  the  grain  and  seed  produced,  except  in- 
the  case  of  alfalfa,  that  crop  being  harvested  for  hay  the  same  as  in  the  livestock 
system.    Some  modifications  have  been  introduced  in  recent  years. 

Crop  Rotations 

Crops  which  are  of  interest  in  the  respective  localities  are  grown  in  definite 
rotations.  The  most  common  rotation  used  is  wheat,  corn,  oats,  and  clover ;  and 
often  these  crops  are  accompanied  by  alfalfa  growing  on  a  fifth  series.  In  the 
grain  system  a  legume  catch  crop,  usually  sweet  clover,  is  included,  which  is 
seeded  on  the  young  wheat  in  the  spring  and  plowed  under  in  the  fall  or  in  the 
following  spring  in  preparation  for  corn.  If  the  red  clover  crop  fails,  soybeans 
are  substituted. 

Soil  Treatment 

The  treatment  applied  to  the  plots  has,  for  the  most  part,  been  standardized 
according  to  a  rather  definite  system,  altho  deviations  from  this  system  occur  now 
and  then,  particularly  in  the  older  fields. 

39 


40  Soil  Report  No.  39:    Supplement 

Following  is  a  brief  explanation  of  this  standard  system  of  treatment. 

Animal  Manures. — Animal  manures,  consisting  of  excreta  from  animals, 
with  stable  litter,  are  spread  upon  the  respective  plots  in  amounts  proportionate 
to  previous  crop  yields,  the  applications  being  made  in  the  preparation  for  corn. 

Plant  Manures. — Crop  residues  produced  on  the  land,  such  as  stalks,  straw, 
and  chaff,  are  returned  to  the  soil,  and  in  addition  a  green-manure  crop  of  sweet 
clover  is  seeded  in  small  grain  to  be  plowed  under  in  preparation  for  corn.  (On 
plots  where  limestone  is  lacking  the  sweet  clover  seldom  survives.)  This  practice 
is  designated  as  the  residues  system. 

Mineral  Manures. — The  yearly  acre-rates  of  application  have  been:  for 
limestone,  1,000  x>ounds;  for  raw  rock  phosphate,  500  pounds;  and  for  potas- 
sium, usually  200  pounds  of  kainit.  When  kainit  was  not  available,  owing  to 
conditions  brought  on  by  the  World  war,  potassium  carbonate  was  used.  The 
initial  application  of  limestone  has  usually  been  4  tons  per  acre. 

Explanation  of  Symbols  Used 

0     =  Untreated  land  or  check  plots 

M   =  Manure  (animal) 

R    =  Residues  (from  crops,  and  includes  legumes  used  as  green  manure) 

L    =  Limestone 

P    =  Phosphorus,  in  the  form  of  rock  phosphate  unless  otherwise  designated 

(aP^acid  phosphate,  bP  :=  bonemeal,  rP  =  rock  phosphate,  sP  =  slag 

phosphate) 
K    =  Potassium  (usually  in  the  form  of  kainit) 
N    ==  Nitrogen  (usually  in  the  form  contained  in  dried  blood) 
Le  =  Legume  used  as  green  manure 
Cv  =  Cover  crop 
(  )  =  Parentheses  enclosing  figures,  signifying  tons  of  hay,  as  distinguished  from 

bushels  of  seed 
=:   Heavy  vertical  rule,  indicating  the  beginning  of  complete  treatment 
II     =   Double  vertical  rule,  indicating  a  radical  change  in  the  cropping  system 

In  discussions  of  this  sort  of  data,  financial  profits  or  losses  based  upon 
assigned  market  values  are  frequently  considered.  However,  in  view  of  the 
erratic  fluctuations  in  market  values — especially  in  the  past  few  years — it  seems 
futile  to  attempt  to  set  any  prices  for  this  purpose  that  are  at  all  satisfactory. 
The  yields  are  therefore  presented  with  the  thought  that  with  these  figures  at 
hand  the  financial  returns  from  a  given  practice  can  readily  be  computed  upon 
the  basis  of  any  set  of  market  values  that  the  reader  may  choose  to  apply. 

THE  MT.  MORRIS  FIELD 

The  Mt.  Morris  experiment  field  lies  mainly  on  the  soil  type  Light  Brown 
Silt  Loam.  This  field  is  located  in  about  the  center  of  Ogle  county  immediately 
south  of  the  town  of  Mt.  Morris.  The  experiments  on  the  major  series  of  plots 
have  been  under  way  since  1910. 

The  somewhat  standard  rotation  and  soil  treatment  methods  described  above 
were  established  on  Series  100,  200,  300,  and  400.  In  1920  a  clover  hay  crop, 
as  well  as  the  seed  crop,  was  harvested  from  the  residues  plots.    Beginning  with 


Logan  County 


41 


1921  all  clover  was  removed  as  hay  and  the  return  of  the  oat  straw  discontinued. 
In  1922  the  return  of  the  wheat  straw  was  discontinued,  as  well  as  the  applica- 
tions of  limestone  until  such  time  as  its  need  should  become  apparent.  In  1923 
the  rock  phosi)hate  applications  were  evened  up  to  4  tons  an  acre  and  no  more 
Avill  be  applied  for  an  indefinite  period.  A  summary  of  the  results  is  given  in 
Table  7. 

Table  7.— MT.  MORRIS  FIELD:     Summary  of  Crop  Yields 
Average  Annual  Yields  1913-1926^Bushels  or  (tons)  per  acre 


Serial 
plot 
No. 

Soil  treatment  applied 

Corn 

14  crops 

Oats 
14  crops 

Wheat 
12  crops 

Clover' 
10  crops 

Soybeans 
2  crops 

1 

0  

45.3 
59.5 
64.4 
64.3 

44.6 
51.2 
62.2 
65.6 

67.2 
43.6 

58.5 
67.4 
70.5 
71.5 

54.9 
59.4 

68.8 
70.2 

70.4 
52.4 

23.3 
28.1 
.34.4 
35.9 

23.5 
25.8 
.32.7 
36.2 

36.3 
24.6 

(1.96) 
(2.53) 
(2.97) 
(2.92) 

(1.61) 
(1.77) 
(2.24) 
(2.23) 

(2.24) 
(1.79) 

(1.56) 

2 

M   

(1.70) 

3 

ML 

(1.80) 

4 

MLP 

(1.92) 

.5 

0       

13.5 

6 

7 
8 

9 
10 

R 

RL 

RLP 

RLPK 

0 

16.0 
18.9 
20.7 

20.0 

(1.68) 

Crop  Increases 


M  over  0. 
R  over  0. 


ML  over  M. 
RL  over  R.  . 


MLP  over  ML. 
RLP  over  RL. . 


RLPK  over  RLP. 


14.2 
6.6 

4.9 
11.0 

-      .1 
3.4 

1.6 


8.9 
4.5 

3.1 

9.4 

1.0 
1.4 

.2 


4.8 
2.3 

6.3 
6.9 

1.5 
3.5 


(  .57) 

(  .16) 

(  .44) 

(  .47) 

(  .05) 

(  .01) 

(  .01) 


(   .14) 
2.5 

(   .10) 
2.9 

(   .12) 
1.8 

-      .7 


'Some  clover  seed  evaluated  as  hay. 


The  outstanding  results  from  these  records  are  those  produced  by  the  manure 
treatment.  Over  14  bushels  of  corn,  nearly  9  bushels  of  oats,  4.8  bushels  of  wheat, 
and  a  half  ton  of  clover  hay  have  been  the  average  annual  acre  increases  in  crop 
yields  from  the  manure  plots  over  the  corresponding  checks.  Residues  alone  have 
also  produced  increases  in  the  crop  yields  altho  the  effect  is  much  less  pronounced 
than  that  of  manure  alone. 

Limestone  has  been  profitably  used  in  both  the  manure  and  residues  sys- 
tems but  the  benefit  has  been  greater  in  the  residues  system. 

The  rock  phosphate,  as  usual,  has  been  somewhat  more  effective  used  with 
residues  than  with  manure,  but  under  present  market  conditions  it  has  thus  far 
not  returned  its  cost,  even  with  residues.  However,  as  noted  above,  applications 
of  phosphate  have  been  suspended  and  the  residual  effect  of  the  accumulated 
phosphorus  in  the  soil  during  the  years  to  come  will  be  awaited  with  interest. 

No  significant  effect  is  apparent  from  potassium  as  used  in  these  experiments. 


42 


Soil  Report  No.  39:    Supplement 


Fig.  2. — Corn  on  the  Mt.  Morris  Field 

The  two  pictures  represent  the  extremes  in  corn  production  according  to  soil  treatment. 
Where  the  untreated  land  has  produced  as  a  fourteen-year  average  44.6  bushels  an  acre,  the 
land  under  the  residues,  limestone,  phosphate,  potash  treatment  has  yielded  67.2  bushels.  The 
most  profitable  treatment  on  this  field,  however,  has  been  that  of  residues  and  limestone,  which 
has  produced  62.2  bushels  an  acre. 


THE  KEWANEE  FIELD 

The  Kewanee  field  represents  in  the  main  the  soil  type  Brown  Silt  Loam, 
altho  a  draw  traversing  the  field  in  a  winding  direction  contains  a  narrow  streak 
of  a  heavier  type  designated  as  Black  Clay  Loam  On  Drab  Clay.  The  Kewanee 
field  has  been  in  operation  since  1915.  The  crops  grown  on  the  main  series  of 
plots  are  wheat,  corn,  oats,  and  clover.  The  arrangement  of  plots  as  well  as  the 
systems  of  soil  treatment  are  indicated  in  Table  8.- 

The  table  gives  a  summary  of  the  crop  yields  by  annual  averages,  including 
the  years  since  the  complete  soil  treatments  have  been  in  effect.  In  the  lower 
part  of  the  table  the  comparisons  expressed  as  crop  increases  resulting  from  the 
respective  soil  treatments  bring  out  the  following  points  of  interest. 

Animal  manure  used  alone  has  had  a  very  beneficial  effect,  especially  with 
corn,  oats,  and  clover.    Residues  alone  has  had  little  effect  on  crop  yields. 

Limestone  used  in  addition  to  organic  manures  has  effected  more  or  less 
improvement  in  all  cases  except  where  used  with  animal  manure  on  the  clover. 

Phos|)horus,  as  usual,  shows  up  to  advantage  on  the  wheat  crop,  and  in  the 
residues  system  the  rock  phosphate  has  produced  a  profitable  return.  A  fact 
which  these  general  averages  fail  to  show  is  that  with  both  limestone  and  phos- 
phate the  effects  have  been  more  favorable  in  recent  years  than  in  the  earlier 
years  of  the  experiments. 

Altho  an  increase  of  3.3  bushels  of  corn  appears  as  a  result  of  potassium 
application,  in  view  of  the  insignificant  response  by  the  other  crops  the  pur- 
chase of  potassium  fertilizer  for  use  in  this  kind  of  a  cropping  system  on  this 
kind  of  soil  would  appear  not  to  be  profitable. 


Logan  County 


43 


Table  8.— KEWANEE  FIELD:     Summary  of  Crop  Yields 
Average  Annual  Yields  1917-1926 — Bushels  or  (tons)  per  acre 


Serial 
plot 
No. 

Soil  treatment  applied 

Wheat 
<^  crops 

Corn 
10  crops 

Oats 
10  crops 

Clover 
9  crops 

1 
2 
3 
4 

5 
6 

7 
8 

9 
10 

0 

M 

ML 

MLP 

0 * 

R 

RL 

RLP 

RLPK 

0 

30.2 
33.0 
35.9 
40.6 

31.4 
33.0 
35.1 
40.6 

40.6 
29.7 

54.4 
64.9 
68.8 
69.7 

55.8 
57.9 
66.1 
70.1 

73.4 
51.0 

58.8 

69 . 5 
72.1 
70.8 

59 . 6 
58.0 
62.2 
67.6 

69.3 
55.3 

(1.65) 
(2.26) 
(2.26) 
(2.33)    - 

(1.55) 
(1.59) 
(1.84) 
(2.01) 

(2.08) 

(1.53) 

Crop  Increases 

M  over  0 

2.8 
1.6 

2.9 
2.1 

4.7 
5.0 

0.0 

10.5 
2.1 

3.9 

8.2 

.9 
4.0 

3.3 

10.7 

-  1.6 

2.6 
4.2 

-  1.3 

5.4 

1.7 

(   .61) 

R  over  0 

(   .04) 

ML  over  M   

(  .00) 

RL  over  R 

MLP  over  ML 

RLP  over  RL 

(   .25) 

(   .07) 
(   .17) 

RLPK  over  RLP 

(   .07) 

The  Phosphate  Experiments 

In  addition  to  the  above  described  experiments  on  the  Kewanee  field,  there 
are  four  shorter  series  of  plots  numbered  500,  600,  700,  and  800,  each  series 
having  four  plots.  Alfalfa  was  grown  on  these  series  until  1922,  when  a  rotation 
of  wheat,  corn,  oats,  and  clover  was  started.  Limestone  had  been  applied  to  this 
land  at  the  beginning.  The  quantity  was  4  tons  an  acre  and  a  similar  dressing 
was  applied  in  1919.  Rock  phosphate  was  applied  to  Plots  1  and  3  at  the  annual 
rate  of  400  pounds  an  acre,  once  in  the  rotation  ahead  of  the  wheat.  Acid  phos- 
phate was  used  on  Plots  2  and  4  at  the  annual  rate  of  200  pounds  an  acre,  it 
being  applied  twice  in  the  rotation,  one-half  in  preparation  for  wheat,  and  one- 
half  before  oats  seeding. 

Table  9  gives  a  summary  of  the  results  obtained  to  date  in  terms  of  average 
annual  crop  yields  and  also  the  corresponding  values  of  the  crops  figured  at 
average  farm  prices  for  the  years  in  which  these  crops  were  produced.  The  rela- 
tive profits,  of  course,  will  depend  upon  the  market  prices  of  the  rock  phosphate 


Table  9.— KEWANEE  FIELD,  Series  500,  600,  700,  800:     Phosphate  Experiment 
Average  Annual  Acre  Yields  and  Corresponding  Money  Values,  1922-1926 


Soil  treatment 


Rock  phosphate 

Acid  i)hos[)hate 

Lime,  rock  phosphate 
Lime,  acid  phosphate. 


Wheat 
5  crops 

Corn 
5  crops 

Oats 
5  crops 

Hay 

5  crops 

Value 
per 
acre 

44.5 
47.3 
40.5 
48.1 

74.4 
73.2 

71.8 
73.1 

74.6 
77.6 
73 . 0 
75.1 

3.46 
3.39 
3.32 
3.40 

.145.63 
46.30 
43.33 
46.32 

44  Soil  Report  No.  39:    Supplement 

and  acid  phosphate.  Acid  phosphate  usually  costs  about  twice  as  much,  ton  for 
ton,  as  rock  phosphate,  and  in  these  experiments  one-half  as  much  acid  phos- 
phate as  rock  phosphate  was  used.  If,  then,  it  is  considered  that  equal  costs  are 
involved,  acid  phosphate  would  appear  to  have  been  somewhat  more  profitable 
than  rock  phosphate,  especially  when  used  with  limestone  and  disregarding  any 
value  for  the  extra  amount  of  the  element  phosphorus  added  to  the  soil  in  the 
use  of  rock  phosphate.  It  should  be  borne  in  mind  that  a  change  of  market 
prices,  either  of  materials  or  of  produce,  might  easily  alter  these  results  even  to 
the  extent  of  reversing  them. 

THE  BLOOMINGTON  FIELD 

The  experiments  on  the  Bloomington  field  are  of  interest  in  connection  with 
the  management  of  Brown  Silt  Loam.  This  field  is  located  in  McLean  county, 
northeast  of  the  city  of  Bloomington.  The  work  was  started  in  1902.  Altho  a 
fairly  long  period  of  years  has  been  covered  in  these  experiments,  the  field  has 
only  a  single  series  of  plots,  so  that  only  one  kind  of  crop  is  represented  each 
season.  The  crops  employed  have  been  corn,  corn,  oats,  clover,  and  wheat;  and, 
since  1905,  they  have  been  grown  in  the  sequence  named. 

On  account  of  irregularities  in  the  land,  results  from  Plots  1  and  10  are 
not  considered  altogether  reliable,  and  therefore,  are  not  included  in  the  figures 
presented.  Since  these  are  the  only  unlimed  plots,  no  conclusions  can  be  drawn 
regarding  the  action  of  limestone  on  this  field. 

Commercial  nitrogen  applied  in  the  form  of  dried  blood  was  used  in  the 
early  years  up  to  1905,  when  crop  residues  and  clover  were  substituted.  The 
phosphorus  on  this  field  has  been  applied  in  the  form  of  steamed  bone  meal 
and  at  the  rate  of  200  pounds  an  acre  a  year. 

Table  10  presents  a  summary  of  the  work  by  annual  average  yields.  The 
comparisons  in  the  lower  part  of  the  table  show  the  effect  of  the  different  plant- 
food  materials  in  the  various  combinations  in  which  they  have  been  applied. 

The  residues  treatment,  supplying  organic  matter  and  nitrogen,  shows  a 
beneficial  effect  on  the  grain  crops,  but  not  on  the  clover.  The  outstanding 
feature  of  the  results  on  the  Bloomington  field  is  the  effect  of  phosphorus  applied 
in  the  form  of  steamed  bone  meal.  In  all  of  the  grain  crops  on  every  plot  where 
bone  meal  has  been  applied  there  is  a  remarkable  i  espouse  to  the  treatment  as 
shown  by  the  increases  in  yields.  This  response  appears  in  all  the  combinations, 
even  without  the  presence  of  residues,  altho  in  combination  with  either  residues 
or  potassium  the  effect  is  accentuated.  For  example,  comparing  Plot  3  with 
Plot  6  (limestone  and  residues  with  limestone,  residues,  and  phosphorus)  we  find 
the  phosphorus  treatment  has  produced  an  average  increase  in  the  yield  of  corn 
of  about  13  bushels  an  acre,  while  the  yield  of  oats  has  been  increased  by  about 
20  bushels,  and  that  of  wheat  by  about  22  bushels  an  acre.  Similar  increases,  tho 
not  so  pronounced,  appear  in  comparing  Plot  5  with  Plot  8  where  potassium  in- 
stead of  residues  is  present. 

Thus  it  appears  that  on  this  field,  under  this  system  of  farming,  the  lack 
of  phosphorus  is  distinc'tly  a  limiting  factor  in  production  and  the  application 


Logan  County 


45 


Table  10.— BLOOMINGTON  FIELD:     Summary  of  Crop  Yields 
Average  Annual  Yields  of  Grain  Crops  1902-1923 — Bushels  or  (tons)  per  acre 


Serial 
plot 

No. 

Soil  treatment  applied 

Corn 

10  crops 

Oats 
4  crops 

Wheat 
4  crops 

Clover' 
S  crops 

2 
3 
4 

L 

LR 

LbP 

.    41.5 
47.5 
55.8 
46.2 
60.6 
48.6 
60.9 
64.2 

44.7 
46.2 
54.3 
43.5 
66.0 
46.8 
57.2 
63.1 

24.1 

27.9 
45.7 
25.5 
49.7 
27.5 
44.5 
50.4 

(   .80) 
(   .88) 
(2.54) 

5 
6 

7 

LK 

LRbP 

LRK 

(   .90) 
(1.19) 
(   .82) 

8 

LbPK 

(2.44) 

9 

LRbPK 

(   .81) 

Crop  Increases 


For  Residues 

LR          over  L 

6.0 
4.8 
2.4 
3.3 

14.3 
13.1 
14.7 
15.6 

4.7 
1.1 
5.1 
3.6 

1.5 

11.7 

3.3 

5.9 

9.6 
19.8 
13.7 
16.3 

-  1.2 

.6 
2.9 

-  2.9 

3.8 
4.0 
2.0 
5.9 

21.6 
21.8 
19.0 
22.9 

1.4 

-  .4 

-  1.2 

.7 

(   .08) 

LRbP     over  LbP 

-(1.35) 

LRK       over  LK 

-(   .08) 

LRbPK  over  LbPK 

-(1.63) 

For  Phosphorus 

LbP        over  L 

(1.74) 

LRbP     over  LR     

(   .31) 

LbPK     over  LK 

(1.54) 

LRbPK  over  LRK 

-(   .01) 

For  Potassium 

LK          over  L 

LRK       over  LR 

(   .10) 
-(   .06) 

LbPK     over  LbP 

LRbPK  over  LRbP 

-(   .10) 
-(   .38) 

'Two  crops  of  seed  on  Plots  3,  6,  7,  and  9  evaluated  as  hay. 

of  this  element  in  the  form  of  steamed  bone  meal  is  attended  by  a  high  financial 
profit.  It  is  of  extreme  interest  to  know  whether  a  similar  response  would  fol- 
low the  use  of  other  phosphorus  carriers,  such  as  rock  phosphate  and  acid  phos- 
phate. Experiments  are  now  under  way  designed  to  answer  this  question,  but 
they  have  not  been  running  long  enough  to  furnish  reliable  results  at  the  present 
time. 

Quite  different  are  the  results  from  the  use  of  potassium  on  this  field.  The 
potassium  has  been  applied  mainly  in  the  form  of  potassium  sulfate,  but  in  1917 
when  this  material  became  unavailable  thru  war  conditions,  potassium  carbonate 
was  sub.stituted.  There  is  a  moderate  increase  in  the  corn  yield  where  potassium 
has  been  used  and  particularly  where  residues  are  absent.  Otherwise,  the  small 
gains  shown  on  some  plots  are  offset  by  losses  on  other  plots,  but  these  small 
differences  are  probably  well  within  the  limits  of  experimental  error. 


THE  ALEDO  FIELD 

An  experiment  field  on  Brown  Silt  Loam  On  Clay  is  located  in  Mercer  county 
just  west  of  Aledo.  This  field  has  been  in  operation  since  1910.  Prom  its  physi- 
cal aspects  this  field  should  be  well  adapted  to  experimental  work,  the  land  being 
unusually  uniform  in  topography  and  in  soil  profile. 

There  are  two  general  systems  of  plots  and  they  are  designated  as  the  major 
and  the  minor  systems. 


46 


Soil  Report  No.  39:    Supplement 


Experiments  on  the  Major  Series 

The  major  system  comprizes  four  series  (numbered  100,  200,  300,  and  400) 
made  up  of  10  plots  each.  The  plots  were  handled  substantially  as  described 
above  for  standard  treatment  until  1918,  when  it  was  planned  to  harvest  the  first 
crop  of  red  clover  on  the  residues  plots  for  hay  and  to  plow  down  the  second  crop 
if  no  seed  were  formed.  In  1921  the  return  of  the  oat  straw  was  discontinued. 
In  1923  the  rotation  was  changed  to  corn,  corn,  oats,  and  wheat.  In  this  rota- 
tion it  was  planned  to  seed  hubam  clover  in  the  oats  on  all  plots,  for  use  as  hay 
or  for  soil  improvement,  and  common  sweet  clover  in  the  wheat  on  the  residue 
plots  for  use  as  a  green  manure.  Since  this  change,  no  residues  except  corn- 
stalks and  the  green  manure  have  been  returned  to  the  residues  plots.  The  lime- 
stone applications  were  temporarily  abandoned  in  1923.  No  more  will  be  applied 
until  there  appears  to  be  a  need  for  them.  The  phosphate  applications  were 
evened  up  to  a  total  of  4  tons  an  acre  in  1924,  and  no  more  will  be  applied  on 
the  west  halves  of  these  plots  for  some  time  at  least. 

Table  11  presents  a  summary  of  the  results  showing  the  average  annual 
yields  obtained  for  the  period  beginning  when  complete  soil  treatment  came  into 
sway.  The  lower  section  of  this  table  gives  comparisons  in  terms  of  crop  increases 
intended  to  indicate  the  effect  of  the  different  fertilizing  materials  applied. 

In  looking  over  these  results  we  may  observe  first  the  beneficial  effect  of 
animal  manure  on  all  crops,  but  especially  marked  on  the  corn.  This  suggests 
the  advisability  of  carefully  conserving  and  regularly  applying  all  stable  manure 
produced  on  the  farm.  Residues  alone  have  been  beneficial  for  corn  but  have 
shown  little  effect  on  the  other  crops  of  the  rotation. 


Table  11. — ALEDO  FIELD:     General  Summary  of  Crop  Yields 
Average  Annual  Yields  1912-1926 — Bushels  or  (tons)  per  acre 


Serial 
plot 
No. 

Soil  treatment 

Wheat 
12  crops 

Corn 
19  crops 

Oats 
lJ^  crops 

Clover 
6  crops 

Soybeans 
3  crops 

1 

0 

30.1 
34.5 
34.6 
36.6 

30.8 
31.4 
33.5 
38.0 

37.3 
30.1 

57.2 
71.1 
74.3 
75.6 

60.1 
66.5 
71.9 

74.4 

76.0 
58.3 

57.9 
64.5 
67.6 
68.2 

59.7 
61.2 
66.5 
68.0 

70.3 
58.1 

(2.21) 
(2.74) 
(3.12) 
(3.05) 

(2.00) 
(1.91) 
(1.96) 
(2.08) 

(1.73) 
(2.38) 

(1.60) 

2 
3 

M 

ML     

(1.63) 
(1.60) 

4 

5 
6 

MLP 

0 

R 

(1.61) 

16.1 
16.5 

7 

RL 

18.8 

8 

RLP 

20.3 

9 

RLPK   

20.9 

10 

0 

(1.62) 

Crop  Increases 

M  over  0 

R  over  0 

4.4 
.6 

13.9 

6.4 

6.6 
1.5 

(   .53) 
-(   .09) 

(   .03) 
.4 

ML  over  M 

RL  over  R 

.1 
2.1 

3.2 
5.4 

3.1 
5.3 

(   .38) 
(   .05) 

-(   .03) 
2.3 

MLP  over  ML 

RLP  over  RL 

2.0 
4.5 

1.3 
2.5 

.6 
1.5 

-(   .07) 

(   .12) 

(   .01) 
1.5 

RLPK  over  RLP 

-    .7 

1.6 

2.3 

-(   .35) 

.6 

Logan  County  47 

Limestone  added  to  the  manure  treatment  produces  no  very  marked  effect; 
when  applied  with  residues,  however,  the  crop  increases  are  considerably  greater. 

The  addition  of  rock  phosphate  to  the  treatment  has  had  very  little  effect  in 
the  manure  system.  Somewhat  more  favorable  are  the  results  in  the  residues 
system,  but  even  here  the  margin  of  profit  on  these  crop  increases  is  too  narrow 
to  assure  the  profitable  use  of  rock  phosphate  applied  in  the  manner  of  these 
experiments.  However,  the  economic  story  has  not  all  been  told,  for  the  applica- 
tion of  lime  and  phosphate  on  these  plots  is  to  be  discontinued  in  order  to  observe 
the  residual  effects.  The  results  of  the  next  few  years,  therefore,  will  be  awaited 
with  great  interest. 

For  the  effect  of  potassium  treatment,  Plots  8  and  9  may  be  compared.  No 
significant  response  appears  as  the  result  of  applying  potassium,  so  far  as  these 
common  field  crops  show. 

A  number  of  problems  have  arisen  out  of  the  experience  on  this  and  other 
experiment  fields  which  call  for  some  revision  of  the  investigations  described 
above,  and  accordingly  certain  changes  are  to  be  made  in  the  future  conduct  of 
these  plots  which  are  intended  especially  to  throw  more  light  upon  the  problems 
of  liming  and  applying  phosphorus.  (See  Soil  Report  No.  29,  Mercer  County 
Soils.) 

Experiments  on  the  Minor  Series 

The  so-called  minor  system  of  plots  (Series  500,  600,  700,  800)  on  the  Aledo 
field  is  given  over  to  a  comparison  of  the  effectiveness  of  different  carriers  of 
phosphorus. 

In  this  experiment  each  series  contains  four  plots.  Plot  1  receives  residues 
treatment  only;  Plot  2  receives  residues  and  phosphorus  in  one  of  the  forms 
under  test ;  Plot  3  receives  residues,  limestone,  and  phosphorus ;  and  Plot  4  is 
similar  to  Plot  3  with  phosphorus  omitted.  On  one  series  steamed  bone  meal 
(bP)  is  used  as  the  carrier  of  phosphorus  and  is  applied  at  the  rate  of  200  pounds 
per  acre  per  year.  On  another  series  acid  phosphate  (aP)  is  applied  at  the 
yearly  rate  of  3331/3  pounds  per  acre.  On  a  third  series  rock  phosphate  (rP) 
serves  as  the  source  of  phosphorus,  applied  at  the  rate  of  666%  pounds  per  acre 
yearly,  and  on  the  last  series,  basic  slag  phosphate  (sP)  is  applied  at  the  rate  of 
250  pounds  per  acre  yearly. 

The  yields  for  all  crops  harvested  on  these  plots  are  recorded  in  Table  12. 
Table  13,  which  is  derived  fi'om  Table  12,  shows  differences  in  crop  yields  pre- 
sumed to  have  resulted  from  applying  the  various  forms  of  phosphatic  fertilizers 
for  the  eleven  crops  harvested  since  tlie  beginning  of  the  applications  up  to  1926. 
In  compviting  these  comparisons  each  phosphate  plot  is  compared  with  its  neigh- 
boring non-phosphate  plot. 

Aside  from  the  soybeans,  the  figures  show  without  exception  more  or  less 
crop  increase  on  the  phosphorus  plots,  no  matter  what  the  form  of  carrier  em- 
ployed. The  difficulty,  however,  of  arriving  at  a  general  conclusion  regarding 
the  comparative  economy  in  the  use  of  these  different  phosphorus  materials  is 
obvious,  for  all  depends  upon  their  relative  cost,  which  fluctuates  from  time  to 


48 


Soil  Report  No.  39:    Supplement 


Table  12.— ALEDO  FIELD:     Phosphate  Experiment 
Annual  Crop  Yields — Bushels  or  (tons)  per  acre 


Plot 

No. 


Soil  treatment 
applied' 


19162 
Corn 

19172 
Oats 

19182 
Soy- 
beans 

1919 
Wheat 

L920 
Corn 

1921 
Oats 

1922 

Clover 

hay 

1923 
Corn 

1924 
Corn 

1925 
Oats 

53.4 

85.5 

18.9 

32.4 

72.8 

48.9 

(2.88) 

83.5 

58.2 

63.9 

61.7 

91.7 

19.0 

34.7 

86.4 

61.9 

(3.25) 

82.7 

66.0 

75.0 

61.5 

90.6 

23.2 

35.6 

87.3 

53.3 

(3.48) 

82.5 

66.8 

73.4 

55.1 

80.5 

22.6 

32.9 

77.7 

47.7 

(2.61) 

88.2 

60.3 

64.5 

55.2 

84.7 

19.5 

33.0 

71.2 

53.6 

(3.17) 

84.7 

57.3 

64.4 

57.8 

87.7 

18.7 

38.3 

87.1 

60.9 

(3.23) 

82.5 

65.9 

76.1 

64.7 

83.4 

23.1 

38.2 

88.1 

52.3 

(3.53) 

77.6 

64.7 

78.1 

51.9 

81.7 

24.6 

32.8 

84.9 

50.2 

(3.06) 

84.1 

51.9 

64.1 

54.3 

83.1 

20.8 

34.2 

75.6 

52.8 

(3.41) 

82.8 

61.2 

66.6 

58.8 

83.3 

23.3 

36.7 

80.4 

63.0 

(3.60) 

87.8 

69.3 

70.3 

57.2 

81.2 

28.1 

36.7 

80.2 

53.3 

(3.82) 

86.6 

70.8 

67.8 

52.1 

81.7 

26.9 

34.1 

82.0 

48.9 

(3.15) 

84.6 

62.5 

66.3 

57.6 

73.8 

18.0 

33.7 

68.1 

54.8 

(2.62) 

74.3 

58.8 

45.0 

56.4 

87.8 

20.6 

38.1 

81.0 

66.2 

(3.66) 

80.0 

69.1 

66.3 

53.3 

78.9 

23.7 

38.4 

83.6 

57.0 

(3.63) 

82.0 

70.2 

66.7 

51.8 

77.5 

21.8 

33.3 

70.4 

59.8 

(2.99) 

82.6 

59.9 

53.9 

1926 
Wheat 


501 
502 
503 
504 

601 
602 
603 
604 

701 
702 
703 
704 

801 
802 
803 
804 


R 

RbP.. 
RLbP. 
RL.  .. 

R 

RaP.. 
RLaP. 
RL.  .. 

R 

RrP. . . 
RLrP. 
RL.  . 

R 

RsP... 
RLsP. 
RL... 


44.0 
59.2 
62.0 
44.6 

43.3 
60.6 
64.4 
47.3 

44.8 
59.2 
57.5 
49.6 

45.8 
60.2 
66.0 
48.2 


'Bone  meal  (bP)  at  the  rate  of  200  pounds  per  acre  per  year.  Acid  phosphate  (aP)  at  the  rate  of  333  J^  pounds  per 
acre  per  year.  Rock  phosphate  (rP)  at  the  rate  of  666J^  pounds  per  acre  per  year.  Slag  phosphate  (sP)  at  the  rate 
of  250  pounds  per  acre  per  year.     All  minerals  applied  once  in  the  rotation  ahead  of  the  wheat  crop. 

2No  residues. 

time.  Furthermore,  the  prices  received  from  farm  produce  likewise  fluctuate; 
and  to  complicate  matters  still  further,  these  fluctuations  do  not  necessarily  run 
parallel  with  those  of  the  fertilizer  cost.  However,  one  may  readily  compute  for 
himself  the  relative  economy  of  producing  these  crop  increases  by  applying  any 
set  of  prices  for  crops  and  fertilizers  which  appear  to  be  most  applicable  accord- 
ing to  prevailing  market  conditions. 

For  the  purpose  of  furnishing  an  illustration  of  such  a  computation,  the 
following  set  of  arbitrary  prices  may  be  assumed  as  representing  approximately 
average  market  conditions  for  the  past  ten  years:  wheat,  $1.25  per  bushel ;  corn, 
75  cents;  oats,  45  cents;  soybeans,  $1.50;  and  clover,  $15  per  ton.  For  the  cost 
of  the  various  phosphatic  materials  the  following  estimates  are  used :  bone  meal, 
$40  per  ton ;  acid  phosphate,  $24 ;  rock  phosphate,  $12 ;  and  slag  phosphate,  $20. 
These  values  seem  to  be  conservative  enough.  The  figures  for  crop  values  repre- 
sent fairly  well  the  average  December  1  farm  price  quotations  for  the  past  decade. 
Furthermore,  it  may  be  pointed  out  that  the  quantities  of  phosphatic  materials 
employed  in  these  experiments  are,  with  the  possible  exception  of  the  slag  phos- 
phate, greater  than  ordinarily  would  be  used,  or  need  to  be  used,  in  good  farm 
practice. 

The  total  value  of  all  the  crop  increases  produced  by  the  various  forms  of 
phosphate  during  the  eleven  years  is  shown  in  Table  13,  as  is  also  the  total  cost  of 
the  phosphate  applied.  From  these  figures  are  derived  the  average  annual  acre 
profits  shown  in  the  last  column  of  the  table. 

Reckoned  on  the  basis  of  the  above  prices,  slag  phosphate  appears  to  have 
furnished  the  most  profitable  returns  of  the  four  phosphorus  carriers  in  the  test, 
producing  an  average  profit  of  $5.16  an  acre  yearly  where  applied  without  lime- 


Logan  County 


49 


Table  13. — ALEDO  FIELD:     Average  Annual  Crop  Increases  Produced  by  the  Various 
Forms  of  Phosphate,  and  Their  Value,  Computed  from  Yields  in  Table  12 

Bushels  or  (tons)  per  acre 


Wheat 

Corn 

Oats 

Clover 

Soy- 

Value 

Cost  of 

Profit 

Profit 

Comparison  of 

beans 

of 

phos- 

from 

per  acre 

treaments 

increase 

phates 

per  year 

2  crops 

4  crops 

3  crops 

/  crop 

/  crop 

//  crops 

//  years 

11  crops 

Bone    meal,    residues,    over 

residues 

8.8 

7.2 

10.1 

.37) 

.1 

$62.93 

$44.00 

$18.93 

$1.72 

Bone   meal,   residues,   lime. 

over  residues,  lime 

11.0 

4.2 

8.2 

.87) 

.6 

65.12 

44.00 

21.12 

1.92 

Acid     phosphate,     residues. 

over  residues 

11.3 

G.2 

7.3 

.06) 

-    .8 

56.41 

44.00 

12.41 

1.13 

Acid     phosphate,    residues, 

lime,  over  residues,  lime .  .  . 

11.3 

5.6 

6.0 

.47) 

-1.5 

57.95 

44.00 

13.95 

1.27 

Rock    phosphate,    residues. 

over  residues 

8.5 

5.6 

4.7 

.19) 

2.5 

51.00 

44.00 

7.00 

.64 

Rock    phosphate,    residues. 

lime,  over  residues,  lime.  .  . 

5.7 

3.4 

1.8 

.67) 

1.2 

38.73 

44.00 

-5.27 

-    .48 

Slag     phosphate,     residues. 

over  residues 

9.3 

6.9 

15.4 

(1 

.04) 

2.6 

84.24 

27.50 

56.74 

5.16 

Slag     phosphate,     residues, 

lime,  over  residues,  lime .  .  . 

11.4 

6.1 

3.8 

.64) 

1.9 

64.38 

27.50 

36.88 

3.35 

Stone,  and  $3.35  where  applied  with  limestone.  Bone  meal  has  given  an  average 
profit  of  $1.72  applied  without  limestone,  and  $1.92  applied  with  limestone. 
Acid  phosphate  has  returned  $1.13  used  without  limestone,  and  $1.27  used  with 
limestone.  Rock  phosphate  has  produced  the  lowest  money  returns,  giving  a 
profit  of  64  cents  an  acre  a  year  applied  without  limestone  and  a  loss  of  48  cents 
used  with  limestone. 

No  consideration  is  given  here  to  the  relative  phosphorus  reserves  which 
should  have  accumulated  in  the  soil.  In  considering  these  figures  let  it  be 
emphasized  again  that  the  order  of  these  values  might  easily  be  shifted  by  a 
relatively  small  change  in  commodity  prices. 

We  may  next  consider  the  results  from  the  standpoint  of  limestone,  which 
was  applied  at  the  rate  of  4  tons  an  acre  to  Plots  3  and  4  of  the  minor  series  in 
1912,  when  the  land  was  still  under  alfalfa.  Another  dressing  of  2  tons  an  acre 
was  added  in  1917,  after  the  present  experiments  were  under  way.  The  effect 
of  this  limestone,  in  terms  of  crop  increase,  is  set  forth  in  Table  14. 

Comparing  first  the  crop  yields  from  Plots  1  and  4,  which  receive  no  phos- 
phorus, limestone  used  with  residues  alone  appears  to  have  been  of  doubtful 
benefit  to  all  of  the  crops  excepting  soybeans.  Considering  all  treatments  as  a 
whole,  the  soybeans  exhibit  a  consistent  gain  in  yield  from  the  use  of  limestone, 
while  oats,  on  the  other  hand,  respond  by  a  consistent  loss. 

In  arriving  at  the  financial  results  for  the  use  of  limestone,  a  charge  of  $2 
a  ton  for  the  6  tons  of  limestone  applied  may  be  made.  This  makes  a  total  cost 
of  $12  to  charge  against  the  value  of  the  total  crop  increases  for  the  eleven  years. 
Figured  in  this  manner,  we  find  a  profit  of  31  cents  an  acre  a  year  for  limestone 
applied  without  phosphate  of  any  kind.  Where  limestone  was  applied  with  bone 
meal,  the  limestone  profit  was  5  cents  an  acre  a  year,  and  with  acid  phosphate 


50 


Soil  Report  No.  39:    Supplement 


Table  14. — ALEDO  FIELD:     Average  Annual  Crop  Increase.s  Produced  by  Limestone 

AND  Their  Value,  Computed  from  Yields  in  Table  12 

Bushels  or  (tons)  per  acre 


Comparison  of 
treatments 

Wheat 
S  crops 

Corn 
4  crops 

Oats 
3  crops 

Clover 
1  crop 

Soy- 
beans 

/  crop 

Value 

of 

increase 

11  crops 

Cost  of 
phos- 
phates 
11  years 

Profit 
from 

11  crops 

Profit 
per  acre 
per  year 

Limestone,     residues,     over 
residues 

1.4 
2.8 
1.9 
-    .9 
3.1 

2.0 

.3 

.5 

-    .4 

.7 

-  .1 
-3.8 
-3.6 
-4.8 

-  5.8 

-(   .07) 
(   .23) 
(   .30) 
(  .22) 

-  (   .03) 

4.7 
4.2 
4.4 
4.8 
3.1 

15.36 

12.52 

12.49 

.57 

6.22 

12.00 
12.00 
12.00 
12.00 
12.00 

3.36 

.52 

.49 

-11.43 

-  5.78 

.31 

Limestone,    residues,    bone 
meal,  over  residues,  bone 
meal 

.05 

Limestone,     residues,     acid 
phosphate,   over  residues. 

.04 

Limestone,     residues,     rock 
phosphate,   over   residues, 

-1.04 

Limestone,     residues,     slag 
phosphate,   over   residues. 

-  .53 

it  was  4  cents.  Used  with  rock  phosphate,  the  crop  increases  were  so  small 
that  a  loss  of  $1.04  an  acre  a  year  was  sustained,  and  with  slag  phosphate,  there 
was  a  loss  of  53  cents  an  acre  a  year. 

Considering  the  small  margin  of  profit  and  the  possible  experimental  error, 
it  is  doubtful  whether  limestone,  used  with  pliosphates  in  the  manner  described 
has,  up  to  the  present  time,  paid  its  cost  on  any  of  these  plots.  The  Aledo  field 
represents  one  of  these  borderline  cases,  so  to  speak,  in  which  the  upper  soil  is 
neutral  or  only  slightly  acid  and  the  lime  requirement,  therefore,  is  not  yet  very 
marked.  As  time  goes  on,  however,  and  cropping  continues,  the  need  of  lime 
may  develop.  It  is  planned  to  discontinue  liming  on  these  plots  until  its  need 
becomes  manifest,  and  in  so  doing  the  annual  cost  of  the  limestone  already 
applied  will  become  automatically  reduced,  so  that  net  returns  which  hitherto 
have  represented  a  loss  may  possibly,  sooner  or  later,  result  in  a  positive  profit. 


THE  HARTSBURG  FIELD 

A  University  soil  experiment  field  representing  Black  Clay  Loam  is  located 
in  Logan  county  just  east  of  Hartsburg.  This  field  was  established  in  1911  and 
embraces  20  acres.  The  soil  is  uniform  with  the  exception  of  a  small  area  in  the 
northwest  part  of  the  field  which  on  the  detailed  map  is  identified  as  of  the  type 
Brown  Silt  Loam  On  Clay.  A  thoro  system  of  tile  has  been  installed  whereby 
good  drainage  has  been  effected. 

The  field  was  laid  out  into  five  series  of  plots,  four  of  which  are  made  up  of 
10  fifth-acre  plots  each,  and  one  of  which  contains  15  fifth-acre  plots,  as  indi- 
cated in  the  diagram  (Fig.  8). 

The  somewhat  standard  rotation,  including  alfalfa  and  the  soil  treatment 
methods  described  on  page  39,  were  established  on  the  five  series.  Some  modifica- 
tions were  made  in  the  order  of  treatment  given  the  extra  five  plots  on  Series  500. 


Logan  County 


51 


n 


Black   Clay    Loam 
Grundy    clay    loam 


i.^  %-, 


fvX]    Brown    S'll    Loam   On   Ctay 
[•!'MJ    Grundy    Silt    loam 


Contour  interval  -  1  #001 


Fig.  3. — Diagram  of  the  Hartsburg  Soil,  Experiment  Field 
This  diagram  shows  the  arrangement  of  plots,  the  soil  treatments  applied,  the  location  of 
the  different  soil  types,  and  by  means  of  contour  lines,  the  natural  drainage  of  this  field. 

These  methods  were  followed  without  change  until  1918,  Avhen  it  was  planned  to 
remove  one  hay  crop  and  a  seed  crop  of  clover  from  the  residues  plots.  In  1921  it 
was  decided  to  harvest  all  the  clover  as  hay.  At  that  time  the  return  of  the  oat 
straw  was  discontinued.  In  1922  the  return  of  the  wheat  straw  was  discontinued. 
The  only  residues  plowed  under  since  that  time  have  been  the  cornstalks,  and  the 
green  sweet  clover  before  the  corn.  On  this  field  the  sweet  clover  has  grown 
satisfactorily  on  the  unlimed  plots.  The  application  of  limestone  was  also  dis- 
continued in  1922  after  amounts  ranging  from  T^/o  to  10  tons  an  acre  on  the 
different  series  had  been  applied,  and  no  more  will  be  added  until  further  need 
for  it  becomes  apparent.  In  1923  the  phosphate  applications  were  evened  up 
to  4  tons  an  aore  on  all  plots,  and  no  more  will  be  applied  for  an  indefinite  period. 
At  that  time  the  rotation  on  Series  100,  200,  300,  and  400  was  changed  to  corn, 
corn,  oats,  and  wheat,  with  a  seeding  of  hubam  clover  in  the  oats  on  all  plots,  and 
a  seeding  of  biennial  sweet  clover  in  the  wheat  on  the  residues  plots.  On  Series 
500  the  rotation  was  changed  to  corn,  oats,  wheat,  and  a  mixture  of  alfalfa  and 
red  clover  for  one  year. 

Since  the  Hartsburg  field  is  located  in  Logan  county,  a  rather  complete 
account  of  the  investigations,  including  a  description  of  the  field  and  a  detailed 
record  of  crop  yields,  is  included  in  this  Report.  The  results  of  the  work  de- 
scribed above  are  given  in  detail  in  Table  15,  but  for  convenience  in  studying 
them.  Table  16  is  presented,  which  gives  the  average  annual  yields  for  the 
several  kinds  of  crops,  including  the  years  since  the  complete  soil  treatments 
have  been  in  effect. 


52 


Soil  Report  No.  39:    Supplement 


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54 


Soil  Report  No.  39:    Supplement 


Table  16.— HARTSBURG  FIELD:     Summary  of  Crop  Yields 
Average  Annual  Yields  1913-1926 — Bushels  or  (tons)  per  acre 


Serial 
plot 

No. 

Soil  treatment  applied 

Wheat 
12  crops 

Corn 
19  crops 

Oats 
H  crops 

Clover 
7  crops 

Soybeans 
:?  crops 

Alfalfa' 
11  crops 

1 

0 

25.6 
29.9 
35.0 
37.2 

30.5 
33.6 
31.0 
35.2 

34.6 
31.1 

46.5 
57.0 
62.9 
61.8 

52.1 
62.3 
66.3 
65.4 

64.3 
51.6 

46.7 
52.6 
58.0 
57.5 

46.0 
54.1 
52.2 
56.3 

55.4 
47.4 

(1.84) 
(2.19) 
(2.32) 
(2.39) 

(1.28) 
(1.67) 
(1.64) 
(1.79) 

(2.13) 
(2.02) 

(1.29) 
(1.64) 
(1.82) 
(1.92) 

25.8 
26.8 
28.4 
26.1 

26.4 
(1.69) 

(3  47) 

2 

M 

(3.67) 

3 

ML 

(3  91) 

4 

MLP 

(4  19) 

5 
6 

7 
8 

9 
10 

0 

R 

RL 

RLP 

RLPK 

0 

(3.33) 

(3.78) 
(3.45) 
(4.04) 

(4.16) 
(3.20) 

Crop  Increases 


M  over  0 . 
R  over  0. 


ML  over  M . 
RL  over  R. . 


MLP  over  ML. 
RLP  over  RL . 


RLPK  over  RLP. 


4.3 
3.1 

10.5 
10.2 

5.9 

8.1 

(   .35) 
(   .39) 

(   .35) 
1.0 

5.1 
-2.6 

5.9 
4.0 

5.4 
-1.9 

(   .13) 
-(   .03) 

(   .18) 
1.6 

2.2 
4.2 

-1.1 
-    .9 

-    .5 
4.1 

(   .07) 
(   .15) 

(   .10) 
-2.3 

-    .6 

-1.1 

-T     .9 

(   .34) 

.3 

(  .20) 

(  .45) 

(  .24) 

-(  .33) 

(  .28) 

(  .59) 

(  .12) 


'No  residues  for  the  first  six  crops. 

The  outstanding  feature  of  the  results  of  the  Hartsburg  field  is  the  large 
increase  in  yields  produced  by  organic  manures,  whether  they  be  in  form  of 
crop  residues  or  of  stable  manure. 

The  behavior  of  limestone  on  this  field  presents  a  peculiarity  difficult  to 
explain  in  that  limestone  has  been  much  more  beneficial  where  applied  with 
animal  manure  than  where  used  with  residues.  Used  with  manure,  limestone 
shows  a  marked  increase  in  all  crops  and  has  given  profitable  returns  on  the  in- 
vestment, while  in  the  residues  system  the  effect  of  this  material  on  several  of 
the  crops  appears  as  negative  and  its  use  in  this  system  has  been  attended  by  a 
financial  loss. 

Rock  phosphate  has  found  its  most  effective  place  in  these  experiments  in 
the  production  of  wheat  and  of  alfalfa,  particularly  in  the  residues  system,  but 
its  effect  on  the  other  crops  has  been  so  indifferent  that,  on  the  whole,  the  use  of 
this  material  has  not  proved  profitable  on  this  field. 

The  addition  of  potassium  in  the  combinations  here  employed  has  likewise 
been  ineffective. 

In  1924  these  plots  were  divided  into  west  and  east  halves  and  some  new 
treatments  designed  to  furnish  further  information  regarding  the  effect  of  phos- 
phorus fertilizers  on  this  soil  were  introduced  on  the  east  halves.  The  west  halves 
were  continued  under  the  old  treatments  except  that  the  phosphate  applications 
were  discontinued  indefinitely  after  a  total  of  four  tons  an  acre  of  rock  phosphate 
had  been  applied.  The  phosphate  applications  were  likewise  suspended  on  the 
east  half  of  Plot  9  on  all  series. 


Logan  County 


55 


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I-H 

56  Soil  Eeport  No.  39:    Supplement 

In  the  new  treatments  bone  meal,  acid  phosphate,  and  rock  phosphate  are 
being  compared  in  different  combinations,  as  indicated  in  Table  17.  These  phos- 
phate fertilizers  are  applied  twice  in  the  rotation,  one-half  in  preparation  for 
the  wheat  crop  and  one-half  ahead  of  the  first  corn  crop  at  the  following  annual 
acre-rates :  rock  phosphate,  500  pounds ;  acid  phosphate,  200  pounds ;  bone 
meal,  200  pounds.  Gypsum  also  is  being  added  to  Plot  9  at  the  rate  of  200 
pounds.  Two  tons  an  acre  of  limestone  were  given  Plots  1-East  and  10-East  on 
all  series  in  1924,  more  to  be  added  in  amounts  necessary  to  maintain  good 
growing  conditions  for  the  legumes. 

Altho  these  new  experiments  have  not  been  under  way  long  enough  to  war- 
rant an  analysis  of  the  results  at  this  time,  the  yields  for  the  three  years  are  all 
presented  in  Table  17  as  a  matter  of  record. 


List  of  Soil  Reports  Published 


1 

Clay,   1911 

2 

Moultrie,  1911 

3 

Hardin,  1912 

4 

Sangamon,  1912 

5 

LaSalle,  1913 

6 

Knox,  1913 

7 

McDonough,  1913 

8 

Bond,  1913 

9 

Lake,  1915 

10 

McLean,  1915 

11 

Pike,  1915 

12 

Winnebago,  1916 

13 

Kankakee,  1916 

14 

Tazewell,  1916 

15 

Edgar,  1917 

16 

DuPage,  1917 

17 

Kane,  1917 

18 

Champaign,  1918 

19 

Peoria,  1921 

20  Bureau,  1921 

21  McHenry,  1921 

22  Iroquois,  1922 

23  DeKalb,  1922 

24  Adams,  1922 

25  Livingston,  1923 

26  Grundy,  1924 

27  Hancock,  1924 

28  Mason,  1924 

29  Mercer,  1925 

30  Johnson,  1925 

31  Eock  Island,  1925 

32  Eandolph,  1926 

33  Saline,  1926 

34  Marion,  1926 

35  Will,  1926 

36  Woodford,  1927 

37  Lee,  1927 

38  Ogle,  1927 


39    Logan,  1927 


{> 


\ 


